I'm certain the graphics is integrated and is not upgradeable. You can use turbocache to use some of your system ram for video ram:
Graphics adapter
NVIDIA® GeForce® GTS 330M with CUDA™ technology
memory amount : 1,024 MB dedicated VRAM (total available graphics memory using TurboCache™ technology can be up to 2,782 MB with a 32-bit operating system and 4 GB system memory)
There's probably a fine balance you need to find to allocate some of your system ram without cutting too much. I would probably allocate 1 g of system ram to video and keep 3 gigs for system ram, assuming you have the standard 4gigs of system ram to start with. If you have the max 8gig system ram then allocate the max system ram for video.