IF money is tight, then I think you did really good.
Get whatever you can out of the 6800GT then when you can afford a 7800GT or GTX or what ever comes out next, sell that 6800GT to a friend or something.... Then again, it's always nice to have a back up card, just in case... I've been in that, "Just in case" situation and didn't have a spare card... So i was S.O.L