Your chipset shares the system memory with the GPU.
There is an option in your BIOS to insrease the the amount of system memory used by the GPU. On a G41 you may be able to raise it to 512 maybe a bit more depending on your mobo, I wouldn't expect too much though. If it's possible add some more ram first and then raise the GPU memory size for best results.
In my BIOS is not any menu about change size of my VRAM. Other ways?
EDIT: I solved, thanks for the answer.