I used to be in the same position as you, and I got a GF4 MX420 PCI 64megger and it was crap. 120 bucks worth too. I'd go for an ATI PCI card, however being without an AGP definately sucks. I think theres an FX 5200 PCI card out there as well. Read up on some reviews and see what you want.
Fallout 2 had sub-par graphics, but that doesn't mean ANYTHING because that game was possibly my number 2 favorite or 3 favorite. #1 would be Land of Lore Throne of Chaos, which also had shit graphics, but it was fun as hell. #2 Half-life of course :-).
I doubt you'll even be able to run Half-life 2 on 1400x1052, considering its so damn good looking, and a laptop just doesn't have the juice that a desktop system would.