Well, your processor isn't bad for starters. Your memory is on the low side, but it should be ok for starting out with Maya. Ideally you'd want at least 4 gb. The biggest thing I would upgrade would be your video card. The least expensive Quadro card, which is guaranteed to work with Maya 2012, is the Quadro 600, which runs for about $149. The least expensive FireGL card that's guaranteed to work is the FirePro V3800, which runs for about $99.

A lot of people will say that they have had no problems with gaming cards, but I've only ever had problems with them. Plus these two professional cards (the Quadro and the FireGL) are cheaper than most gaming cards. Just make sure that these cards can fit in your case before you buy them!