Any card with an s-video output will be able to hookup to the tv. When you are buying your new gfx card make sure you look for this feature. If you don't game then a low-end card with an s-video output would work just fine. Once you get your card you will need an s-video cable to go from the s-video port on your gfx card to the s-video port on the tv.
EDIT: you will also want to check whether your motherboard uses AGP or PCI-Express to determine which video card you need. If your looking for a low-end AGP card with s-video this should do just fine:
Here is a cheap PCI-Express card with s-video output:
Of course if you like to game then you will want a nicer video card, but those two are perfectly fine for just hooking your tv up to your computer. Don't forget an s-video cable too!