Low fps, probably need a new graphics card - help?

[Canniballistic]

As for my budget when it comes to a new card - well, kind of hard to set a limit really, seeing as prices in your country will probably differ from where I'm from. But I guess it's safe to say you can skip the horribly expensive cards though.

New card $100-$150AUS
New case $40-$50AUS

EDIT: These are inflated Australian prices for basic gear that would run the game fine. You could get them cheaper if you looked around. Its just a ballpark figure to get you going.
Also I suggest you talk to your local PC hardware retailers and discuss the matter with them. If they are half as competent as they should be they should be able to give you alternatives and prices that you could even bring back to these forums for people to give you their opinion of.