And to answer your second question-- no you cannot change the video card in a laptop. Laptop cards are soldered to the board.
That isn't 100% true. There are laptops with dedicated video cards that are not soldered into the motherboard. I know this because I replaced the ATI graphics card in my Dell laptop with an Nvidia card. The only issue is that it MUST be the same size/dimensions as well as connection (mini PCI-Express is what mine was). The Nvidia card came from the same model laptop but a different revision, so it fit perfectly.
If you are not sure something will fit though, I wouldn't bother wasting your money and possibly your laptop trying