Try nVidia GT 540M 2gb graphics card. I am using from last 2 years till now no maintenance is required. The nVidia GT 540M is good enough to play many games with medium settings that are not too demanding. I have also played Max Payne 3 on it with medium settings and there is no lags in video performance at all. So i will recommend it.
I can't even remember the graphic card in my computer but it came with 2GB of memory and it is good to play any game. I do have a higher processor than yours.
nVidia cards have always worked for me so I'd go for that option. Nothing against ATI.
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