changing virtual memory on Dell i7348

Hey,

I want to play Assassin's creed Freedom cry game.The minimum size of the VRAM should be 1024MB.I see that the current VRAM size is 128 MB. I tried to change it using setup. I see that I can't change it manually. Is there any other way to deal with this ? Is there any software that might help me ?.

Thank you in advance