I was looking to upgrade my graphics card so i can play alot of the new games on max graphics. I have a GIGABYTE Radeon HD 7870 2GB 256-bit GDDR5 right now and its works great but I'm always looking for upgrades. I'm not in a big rush but I'd say the highest I'm will probably go is $400 for now. I've also heard that if my processor is too "weak" it will affect the graphics card so ill post my specs below.
It would be nice if you had the i5 3570k so you could OC it it easier and higher. They hit 4.0 no sweat and close to 4.5 with no voltage changes. That being said, your CPU really isn't weak. Nor, for that matter, is your card. 7870 GHz to a 7950 isn't much of an upgrade, so if you're really wanting to go higher soon, 7970 is your best bet in the AMD camp or the 670 in Nvidia.