Hi
I have moved your thread to SimCity (2013) forum 
The VRAM is the RAM memory of your graphics card and, unfortunately, it doesn't increase to fit the game's needs.
Could you please give us more technical information about your computer? A dxdiag would be very helpful. You can find instructions on how to get a dxdiag here, and you can attach it to your answer. In the dxdiag, we can check if your computer has another graphics card powerful enough to meet the game requirements.
Thank you,
Mai