Firstly I think we need to understand what you've got.
Could you go Start -> Run -> Then type "DXDIAG" if it comes up with a yes/no box choose no then select the 'display' tab. It should tell you what graphics card you're running.
You can't be running a Radeon 6500 and run modern games, it would be impossible. You could be running a Radeon 9500 as they were common enough back in the day.