Not an expert opinion, but I'd install another card if you have an open expansion slot. Doesn't have to be anything uber-gamer, l33t, or anything like that. I'd bet you could get a nice price on a 128 MB video RAM card -- sorry, haven't priced them, lately -- just an example -- 128 is not even close to top end, anymore...even a 64 MB card would obviously double your ability.
It would make the rest of the RAM available to the computer, too.