sorry it's not going to happen. the pcmcia slot has no way of interfacing with the laptops screen so even if it were possible you would need to use an external monitor which defeats the purpose of having the laptop. you can't fit a gpu in the pcmcia slot or at least certainly not one that would be worth using.
there is ONE that was reviewed by MaximumPC a while back...But it wasn't very good and it was like $250...it's almost more worth it to you to see if the built-in graphics are upgradeable