your stuff is pretty out dated but if you don't want to spend a lot i'd just get one of these:
http://www.amazon.com/EVGA-GeForce-Mini-HDMI-Graphics-01G-P3-1526-KR/dp/B00549HZ7S/ref=dp_ob_title_ce
It will simpler games fairly well.
You definitely won't be maxing out settings at high resolution.
If you wanted to upgrade components i could "build" you a machine and help you out.
Been building computers on the side for people for over 10 years.
Anyway, good luck.
keep me posted if you'd like further help.