Get a gtx 260 from EVGA for only $225!!!

[Soleron]

HD 4870 beats it in about half the games and is on Newegg for $254.99 after rebate or $274.99 without a MIR.

So get an HD 4870. It's much cheaper than your GTX260 and it's on average the same performance with the occasional victory over the GTX280 too. (source: techreport.com)