You might as well upgrade, 5 and 6 series cards are so dang cheap now. Kinda wish I would of held out a bit before I bought my 2 7970's because it's overkill on everything i've tried. League of Legends gives me like 650fps, get like 140 on BF3. And i'm running 5760x1080 resolution across 3 screens.
Grab one of these or something http://www.newegg.com/Product/Product.aspx?Item=N82E16814102948