Your GPU needs to be of the speed of a GTX550/Radeon HD7770 or higher. Use a speed comparison website like GPUBoss's gaming bar to give you an idea as you will have to worry more about shader processing power than GB's of RAM onboard. You will be running at absolute lowest settings to fit the graphics on your small GPU RAM though, but can get it running pretty smoothly. Your CPU is fine, but you will want to upgrade your RAM to 6GB to be able to load into matches reliably whilst online, otherwise RAM thrashing will cause you to timeout and disconnect often. That is absolute lowest, and I have experimented a lot with playing GTA as my partner wanted to play in the house with me, but on a media server with a 2.4Ghz Q6600 quad.