Upgrading from my 4870 1gb card

I need a little advice on a upgrade to my gpu. I recently built a new amd based build and kept my 4870 from my old build. 4870 is starting to show alot of artifacts across the screen and might be on its way to failure. All in all im looking to buy a new card for a little extra performance.


Amd 1090t cpu
corsair h60
corsair 750w psu
8gb ram
Antec 900 v2 case
aging 4870

Now I game on my 32 moniter at 1360x768. I dont plan to upgrade anytime soon to a higher res screen. Trying not to buy something thats overkill for my resolution setup but also not trying to buy another card in a year. My budget is around 200 and can go above if its worth it.

Games in rotation at the moment.
APB
nba 2k12
battlefield 3
L4d2
Rage
Saints Row
Batman


I was thinking 6950 as a upgrade because I can get those for about 200 on ebay. Any help will be much appreciated.