I need a non-expensive video card so I can play The Sims 3?

Well, I love to play the Sims 3, but I recently found out that the reason my Sims game has been going bad, (Like going black and then you can see the game and then repeat. Until the power of the computer finally goes off) is because my computer has a really crappy video game card I guess. So I need a new one but it has to be kinda cheap because my dad is really annoying and doesn't like to get very expensive things for a computer. Also it's a Dell Inspiron 530S if that helps. And yes it's a desktop.