ATI Mobility Radeon™ HD 5470 - 1GB

your cpu and rest of the specifications are good enough except for your graphic card i.e. ATI Mobility Radeon™ HD 5470 ,it is a lower end gc it can handle newer games at low resolution and maybe medium to low settings...but the game you mentioned like GTA 4 it is a gpu killer even on the high mid range gc's it cause problems to play...so forget about playing it on high resolution but still you would be able to play it on lower resolution

The HD 5470 is not considered a gaming card and 1GB of RAM on that thing is a waste.

If you want to play GTA 4 then I recommend buying a PS3 or Xbox 360. It is simply not worth playing on a PC. It is a very poor port of a console game and as a result it has high hardware requirements.