What kind of cards are available for a mid-age PC?

Being as you are limited on funds,you might look into something like the
ATI 9250.
It is an 8X AGP card that will run at 4X,but you will benefit form faster
clock and graphics processor speeds.
You won't have the full bandwidth but it will be a good starter card when
you deecide to upgrade your motherboard.
It is also directx9 compatable.
Depending on the manufacurer,you can find them from about $50-$80.

if you dont have alot of money like 40-70 go with the radeon,9250 or 9550 the problem with those is that they wont actually perform better then your TI, but they will be able to run the newer games.
if you have abit more money 70-100 i would go with 9600pro which is probly more increase in performance.
if performance isnt a big thing and you want a card that will last for a long time i would look tward the geforce 6 line, i have a 6200 which performs well enough after i tweaked it.

if you want good performace go with the 6600gt which goes from 130-160 or so, it was out of my price range but it one of the the best 128mb cards around.

provide a budget and ill see what i can do to help you out. good store to buy computer parts from include www.newegg.com www.mwave.com www.zipzoomfly.com

a good videocard for the best bang for the buck would be the ATI X800XL. but first provide a budget.