a 6850 is the best card at 150 for that resolution. It will max almost any game at that resolution.
You can find 6870 for $140 AR all the time on newegg, just wait untill one of those deals comes around. I'd also check craigslist and see if there is anything localy. I just got gtx 470 for $80!!! And, yes there is nothing wrong with it.