I would say to go for a i3 2120 ($120) or a i5 2400 ($190)http://www.newegg.com/Product/Product.aspx?Item=N82E16819115077
- i3 2120http://www.newegg.com/Product/Product.aspx?Item=N82E16819115074
- i5 2400
Phenoms are quite old and the dual-core i3 2120 beats the Phenom 965 in most tests. Battlefield 3 uses 4 cores online so I would try to get the i5 2400 or you could wait next year in March for an Ivy Bridge. You do know that you will have to upgrade your mobo and memory to swap the CPU. I don't think it's worth it to buy a CPU now though. Your current rig is actually quite decent and you could save up next year for a Ivy Bridge 3570K (2500K equivalent). Just start OCing your GPU and wait until Ivy Bridge comes out.