This would probably be best in the Help forum, simply because you have people like O_o that know heaps about this stuff.
First of all, it'd be great to know what your current computer specifications are, and how much you are considering spending?
Video cards are very easy to install, and a lot of them are cheap (unless you only have AGP slots, opposed to PCI-e). Installing a new CPU and RAM is quite easy too, so long as you buy the right ones for your motherboard.
So yeah, more information, and perhaps I can tell you some more and recommend some hardware.