Can I upgrade the video card in my toshiba satellite P305 laptop?

I have a toshiba satellite P305-8906 laptop with an ATI mobility Radeon 3650 HD video card. I was looking to upgrade to a 1GB video card. I'm not sure which in the 4000 series I should get or if it can even be done. I talked to a local computer tech and he wasn't much help, so I tried those "experts" down at Best Buy and they weren't much help either.|||Laptops have a video chip that is built into the motherboard. They cannot be upgraded.