I would lean that way fast my self.. radeons can be ok cards for maya, I haven't heard much about the 7500's. Maybe you could try to see if they have updated drivers for it at there web sight ?? also when you do I would save every update you get.. becouse they could mess something up in there next verstion. You might also do a serch on the board hear with radeon or card. something like that to trak down some post that I remember whare they were talking about radeons.. what worked ,, what didn't.. etc..

BTW the rest of your computer sounds fine.. 2.4ghz.. is plunty of power.. 256ram will run maya but you get your stuf to a some what complex state.. your going to have some slowdown..

about all I can think of at the moment..