After reading the "Best Graphics Card For The Money: August" article, I've decided on a ~$150-250 budget. Ideally, I'd want to spend $200 at most, but if the upgrade is substantial enough, I'd be willing to spend a bit more.
So this brings up the options of GTX 650 Ti BOOST, HD 7850, HD 7870, GTX 760, and HD 7950.
I'm not sure which card I can run the best without bottlenecking, overheating, etc. with my current setup. More details as follows:
You dont need 850w PSU go for 550w is good enough
Also dont get 4 channels ram take 2x2gb or 1x4GB and in the future u can add one more 1x4gb and AMD Phenom II X4 955 Black Edition support DDR3 1333mhz ram.
So after looking into it it looks like with some overclocking I will be able to handle even the GTX 760. I guess now I just have to decide how much I'm willing to spend. I don't do too much intensive gaming so I might go with the 7870. Thanks for the help.