GTA4 is the worse designed PC game i have ever seen... it has many built in limitations and restrictions on what you can set it to based on your hardware. i was running 9800GT 512MB cards in SLI and it would not let me max out certian settings as i was "over my video cards ram limit" made no notice to the fact the game was installed INTO my ram. (ram drive) its a very crappy game. even with my 5870's it wont let me max some settings. i enjoy the sand box, hate the restrictions imposed.
in either case, the i3 is not a gaming chip, its a low end internet browsing chip meant for basic computing and battery life in laptops. if you lower all the settings it might run bit im sure it will glitch from time to time. see if your laptop has a PCI-E slot and buy a new video card for it if it does.