You have a laptop. There is no available option to upgrade your video card. It is integrated into your motherboard and there is no 'additional' slot to plug in any type of expansion video card. Asus did make one IIRC for a few of their gaming laptops, but I'm not sure they still do that or if it was a demo.
When you buy a laptop, your upgrade options are very limited, period. You'll be able to install more RAM, change the hard drive and maybe use some external sound card or other adapters through PCMIA slots, but thats it.
Your Intel Video Chipset isn't designed for gaming period, some of the higher end laptops with dedicated video card built into them from ATI or Nvidia can pull of some not too bad performance in games, but Desktops will always be superior in that aspect.