TCM,
1. I am reasonably sure you need a new video card and you *should* be able to get a 16mb one for a little around the high end of your price range, if not less.
2. Memory is still cheap and I always believe that the more ram you got, the better off you are. It's been one of the cheapest ways to 'upgrade' your pc and get the most bang for your buck.
Note: This is all my opion. Feel freee to see other doctors to put your mind at rest...
Not sure on where to get the best deal on a buy, perhaps some other members can help in that regard....
Hope this helps.
/JD