It does not look like this mobo supports PCI Express 2.0 which pretty much locks you out of the mid range GPU market. I found a 6850 on newegg that would be supported on your mobo provided you have enough juice and space in your case. http://www.newegg.com/Product/Product.aspx?Item=N82E16814129272 Anything newer than this your probably going to have to do full systems upgrade, the 6850 is still a decent card though.
It does not look like this mobo supports PCI Express 2.0 which pretty much locks you out of the mid range GPU market. I found a 6850 on newegg that would be supported on your mobo provided you have enough juice and space in your case. http://www.newegg.com/Product/Product.aspx?Item=N82E16814129272 Anything newer than this your probably going to have to do full systems upgrade, the 6850 is still a decent card though.