Well you could go for an ATI graphics card, quality on them is more than adequet, but then... that of course means replacing your existing graphics card. You can get a 9600XT for just over ?100, or go for a 9800pro which are about ?150.
But if your wanting a bog standard pci tv out card, you might be best going for a capture card with tv out. Get the best of both worlds
They range from about ?40-?100