[Leftos]

Well, my recommendation for a good 60FPS steady experience (I can't stand stuttering in sports games, as much as I don't mind it in FPS games for example) would be a dual-core CPU with at least 3.2GHz on the clock (although overclocking is there for the more experienced/adventurous), a standalone GPU with decent juice (although NBA 2K12 didn't tax my NVidia GTX 460 more than 30%) and to get all that on your PC, you'll definitely need a better PSU.

Your PSU is at the absolute bare minimum, so any upgrade is a no-go with it.

Sounds to me like you're up for a major upgrade if you're to enjoy 2K12 on your PC on 1080p 60FPS. An i3 + an NVidia 550Ti + a decent 450W PSU would cost you around 300 euros (~$400) here in Greece, so keep that in mind.

You might get decent performance out of lower specs as well, but I haven't been able to enjoy 2K12 on anything less than 60FPS on my monitor's native resolution (1080p), that's why I'm recommending this. Up to you and how much money you can/want to spend.