Can You Buy New Video Cards for Laptops?

I have a GMA HD it runs games like CoD BO, and Crysis 2 at playable fps. But I would love to place a new video card in my laptop. I use an Hp dm4t, and I would like to buy a new gpu for it. If I can do it, can some of you recommend new video cards for under 125 dollars that tare good.