I'm selling my 360 and several games, and netting myself a job, so I'll have around $500 by the summer.

Dealio, I want to upgrade my computer to run BF3 and pretty much any game on the market at high settings. My current loadout:

Intel Lenovo PC
Nvidia 520 GT

Pretty much everything else is factory.

So, this is what I'm looking for, and try to explain it as best as you can for a PCnewfag.
I need myself:
A better processor
A better graphics card
A better power source

Remember, all of this with a budget of $500.

Bump.

If it matters, I can run Call of Duty 4 on Medium/High Graphics, which already looks better than most 360 games.

A better processor
A better graphics card
A better power source
what kind of fucking processor slot do you have? graphics? probably pci-e 2.0 x16? what kind of power supply? c'mon brah