If you have Ati stay with a new Ati card same goes with Nvidia. Its hard to go from one to another without a reformat being done. Hope i didn't confuse you. Here... go to device manager and click on display adapter. whats it say ?

Also you may try to OC your processor. I did mine from 3.4 stock up to 4.2 stable and that really helped out my frames. its maxed 299 the whole CSS video stress test.

Once i know what card you have now i can point you in the right direction.