Selling Your Game at GenCon

Well I'd like to have a booth at Origins, but it's too soon at this point for me to go there. I should explain my background etc. for my plans with my game.
I'm not interested in having my game published by another company, mainly because the percentage pay is too small. 5% just seems like a gyp. Although it's obviously more perservering to self-publish a game, it's a lot more rewarding. Not just because of getting all profit (I'd be very suprised if I actually made any decent of profit on this. I'm not expecting it), but because you have control of how you want your game designed, and it's more rewarding to know that you did something cool, and you can look back at it when you're 40 and go "yeah, that was fun. I have no regrets."
But anyway, right now I'm just doing research and number crunching. I'll be making a decsion by early June as far as whether or not I'm going with this. I'm still working on a budget, and researching costs for various parts for my game (cards, dice, etc.) which I'll have completed research by the end of this week. I'm also making a plan with possibly going to GenCon (hence this thread) and selling my game there. I'm making a plan A B & C for if I were to break even with costs, not break even with costs, and the highly unlikely scenario that I sell out and need more copies. I know the 3rd scenario won't happen, but the thing is that I want to have a plan and be prepared for all possible scanarios without any unexpected calamities.
Based on my budget so far, I need to sell 500 copies of my game to break even with costs. Those costs include all startup costs, registering a trademark, cost for GenCon, and of course the game itself. I'm sure it seems very optimistic to think that I can even sell 500 copies, but I think it's something that with proper research and all, it's something worth taking the risk for and seeing if it works or not.
Also, I have two friends/fellow playtesters who might be going with me to GenCon to help me out with selling my game there if I do this. I'm driving to GenCon if I go. Plane is too expensive. I don't mind the 9-10 hour drive. I have all of that budgeted.
I should also mention how I did playtesting for this, but I'll save it for another reply or thread since this reply is long enough.

I should of mentioned the budget more clearly. The whole thing with needing 500 copies to break even with costs. Those costs aren't just for the game itself. If that was the case, I would only need to sell a little more then 200-250 to do that. The 500 copies also covers paying for the costs of GenCon (if I decide to do so), trademarking the logo and name of the game, startup costs etc. Also, I decided not to do an ad. Knowing now how large the conbook is, it would be ineffective. If it was a small 50 page thing, it would be different, but I'd be throwing money away putting an ad in the GenCon book.
My game is a card game who's main influences are European games and Magic, except (I really need to emphasize this) does NOT play like magic. If someone were to play it, they might see the influence with the abilities on the cards, but there's nothing mechanics wise that works like it or anything. The main mechanic of the game revolves around bidding, and strategically trying to get all your cards in play first. There's abilities on cards that give you advantages etc. and effects on the overall game. There's also a couple other cards that deal with alternative ways of winning or getting cards in play. I don't think I explained that too well.
I want to mention the playtesting process better with how I'm doing that. Basically, I'm doing two steps of this. First is playtesting with my (emphasis on this) brutally honest friends. They're not afraid to say "This needs to change. That part sucks. What is this?" I've had at least 5 playtest sessions with them on my game, and their feedback has been really valuable to making improvements on the game and taking out all the uneseccary stuff. The problem with my game when I first playtested it was that it had too much stuff. It was like trying to cram two different games into one, so I took out a huge chunk of it, which will eventually be going into a seperate game on its' own. After I simplified the game, for the first time it made sense to everone, because up until then, they couldn't comprehend that and they all said "It's too complicated. You need to fix this." So now that the main structure of the game is worked out, I'm now just doing small tweaks with gameplay. The game is a 3-5 player game, however, I'm making a 2 player variant of the game as well. Althought it uses all the same cards as in the 3-5 player version, it's a different animal from the multiplayer version, which it has to, otherwise it wouldn't work. Once all that is all done, I'm then doing the 2nd step of playtesting, where I'll be playtesting at a local gamestore called "Millenium Games and Hobbies", which is just outside of Rochester, NY. I'm going to be playtesting with the European boardgaming group there, and also try it with the Magic group as well to see if they'd actually like it or not, since I'm looking at those two demographics. Mainly the European board gamers and other trading card gamers. Although this game is NOT a trading card game, and doesn't play like one, it might be appealing to some TCGers that you don't need to spend hundreds of dollars on cards to have many different possibilities of a game. But anyway, when I do playtesting there, I'm not even telling them that I designed it. I'm just "playtesting for my friend who designed this game, so let me know if you see anything wrong with this, or if you like this". I'm not going to have the game printed until July, so I'll be playtesting until the end of June.
As for the graphics, I designed them myself. It's a simple design, but looks professional, and looks the way I want it to. The theme is a bit of a concern for me, but I'll talk more about that on another reply since this reply is long enough.

That's a very good reference to have. It does seem crazy to have a game that's entered what I consider "final" stages of playtesting to even think about selling it at a con. That's why I'm looking into this now before I actually do anything with it. I want to make sure my decision to go ahead with this is based on thurough research and playtesting. I have until early June to make my decision with this, so I'm very greateful to be getting all the excellent feedback and recommendations everyone has been giving me on this. Next Wednesday will be my first playtest with people who have never played the game before, and I know that will add a very important perspective to the game, and determine if it's actually any decent or not. The playtesting that I've done so far with my brutally honest friends has let me be able to develop the game from a complicated thing with too much stuff in it, into something that's workable, and now (so far) only needs details worked out. Details like "Win 2 modify cards instead of one" "bidding works like this instead of like this". Small things with gameplay such as that.
I've also been working with my budget and have been able ot cut a few costs by a lot, but the budget still isn't final yet, so it would be a waste of time for me to put it on here only to have it changed the next day. Thanks again for your insight :)