Everything else looks good except for your graphics card, that card is a bit too weak.
You'll be able to run Modern Warfare 3 on Medium - High with a reasonable resolution perfectly fine.
You'll be able to run GTA 4 around Low - Medium settings with around 25-30 FPS.
I'm not fully sure about max payne, but take a look at their minimum system requirements.
As for Battlefield 3, you'll be able to play on Lowest resolution and Graphics with around 25- 30 FPS.
Other then that your pc is fine.
I'd suggest getting a 9800GT or a Radeon HD 5770, they arn't that expensive and they have great performance for a budget. You'll get around 45-50 FPS in most modern games.