Get a PCI card...as you might have noticed by now...I gave you an AGP card...and since you don't have any AGP slots, just PCI I advise get a new card...we just got...the GeForce FX 5200...and that works...so get that.
£50 from PC World.
And it has 128mb, more than enough for anything out there at the mo...the only problem is...the drivers are little buggers to load...