This model has 2 gpu's - an embedded Intel Graphics gpu plus the dedicated nVidia 9400m. While you cannot upgrade the 9400m VRAM, you can increase overall RAM in your MacBookPro. Since the embedded Intel Graphics gpu utilizes shared RAM you may see some improved graphics performance by upgrading system RAM. I noticed a substantial improvement when I upgraded from 4GB to 8GB RAM.
I have the same model MacBookPro, and I must say that after monitoring performance over the years, I have not found any situation where the 9400m improved graphics performance over the embedded Intel gpu. But the 9400m does make the MBP run hotter and decreases battery run time. Needless to say, after time i decided there was no benefit to running the 9400m. (And I do use Photoshop, Aperture and Final Cut.)