The CPU can handle Low-Medium mixed settings with high FPS spiking but you will need at least a 9800 GT 1GB For even Low. A 660 2GB is preferred as is a Quad Core @ 2.4ghz and above.
There are a lot of videos that show you how to tweak settings files for GTA and make it look like nintendo 64,so you can make it run but it will not be a nice experience.