You have not mentioned what resolution you are playing games.
For 1600x1200, High Quality, GeForce 8800 GTX SLI(best choice)
1280x1024, High Quality, GeForce 8800 GT 512MB
1280x1024, Medium Quality,Radeon X1900 XT 256MB
1024x768, Medium Quality, Radeon X1950 Pro 256MB

I am not sure about prices or availability in Doha. Check out at Sofitel.