That's an old, slow (for gaming) video card. Replace it with something like Radeon 1650 Pro or an Nvidia Geforce 7600GS or better 7600GT Either of these will let you play almost any game released in the next 12 months or so.
Make sure you get AGP Not PCI-express.
Shop around and you'll pay about £50-£60 You could spend more on an AGP card but not really worth it unless you have faster components, and yours sounds about 3-4 years old already.
Out of interest what game was it?