Ask about the computer's processor

Yes a dual core processor is at least needed.Dual core was better than Core 2 Duo but now it's way too old that's hard to find in the market on today's date.

Dual core is okay for games like GTA. But its not only the processor you must look after. There are also two boards that are as important as the processor. These are the RAM and the video card. RAM or the Random Access Memory also is important for the speed of your unit and the Video card is needed for high quality of graphics and video adaptation of your unit. I think it will help you a lot if you look for new units in the market specially designed for gaming. Look specifically in the specifications and observe which specs are increased and upgraded from the usual standard. And then try to copy those specs in your computer. Good luck!

Dual core could very well play that game with a good video card and RAM, but the temperature issue is considerable as compared with a core2duo having four threads to process data. 1.6 ghz core2duo would be more faster than the 3.2 and would run all games smoothly, but definitely a good performance video card of 1 gb RAM would surely do the trick playing such high graphic likes GTA4.