Even if there WERE graphics cards out there for laptops, you would have to completely disassemble the thing to get to the motherboard so you could hook it up. I had to replace a laptop motherboard once, it took forever, not to mention the tool sets I had to buy for the special screws. So assuming there are graphics cards for laptops (which I doubt) they would have very little power because the heat from it would build up inside the case and ruin it.