Unfortunately, no. In almost all laptops, the graphics card is soldered to the motherboard or simply no other graphics card would fit. There aren't many laptops that offer upgradable GPUs (Sager is the only one that comes to mind, but I might be wong), and it's usually a big selling point. One option, however, is to possibly purchase an external PCI slot and install a desktop graphics card into that, which would however hinder portability.