Re: On to 5th video card in a year.......
Wow, you do realize that whoever bought that card was someone who had stolen the account? I'm not sure what Amazon does for these things, but hopefully since you already shipped it, they cover any and all costs from fraud. I had sold my original Xbox for $300 (this was after the Xbox 360 had come out) to someone who wanted me to ship to Africa or some random place. He paid me already and everything but never returned my emails for an address. So I resold the Xbox after a month of waiting and made about $150 off of it, which was about all I could have gotten.
Then, come 2 months down the line (after I've spent the money on a 360 and games), I get an email from eBay telling me I have to refund the money immediately because the account was stolen. They said if I had I shipped it out, I would have been fine, but since I hadn't shipped it yet, I was left with losing that $300.
So hopefully since you already shipped it, you will luck out. Just keep your eyes open for those willing to pay big $$$ and have it shipped half way around the world.
EDIT: Now to actually reply to your question, yes that sounds like a possitive strategy. The 9800GX2 would perform better, but would cost much more. So I think your best option for a good card and the step-up would have to be the 9800GTX.