i thought i repliead with 2 128mb pci graphics cards in another thread?
anyway, msi, abit, gigabyte to name a few all have reliable motherboards that will no doubt outperform what you have, look around the shops like ebuyer.com for the idea of what ya get for your money, they also have ratings there too...
No AGP? At 2.6 Gigs? I would expect it to have had one; my 1.4 had one; probably just eMachines.
Best idea is a new Motherboard; but it'll cost you and you can't be sure it'll work with your Celeron - although it probably will. Then you won't get built in graphics; so you'll need a Card like the 5200 that Camers recommended. It'll be cheaper and easier to find that a PCI version - but all of that for $150? I don't know.