Then change the video card and possibly the power supply if needed. This neatly gets around all the pain involved when folk build their first machine.
What video cards? Use http://www.tomshardware.com/reviews/best-graphics-card-game-performance-radeon-hd-6670,2935.html to see what's best for the money.
Bob
I'm a novice, a family man, and on a budget. But I have been using computers to work and play for close to 30 years. I want to learn how to build a reliable machine to edit photographs and play the latest RPG's and TBS's for a reasonable price and will stay current over a few years.
Thanks!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic