Laptop graphics

My eyes may have been bigger than my stomach, metaphorically speaking :ouch: Help! I have a 2-year-old Asus X550CA that I mostly use on my desk with an external monitor. Not a gamer, not particularly techy, but I do like a crisp image, I often watch videos, and I tend to have multiple windows...

I have HP 630 laptop with Intel(HD) Graphics providing me 762 MB video memory, Windows 7 OS, and a 2nd gen Intel core i3 processor with 2 GB RAM. How can I increase its available video memory so that I can play games like Batman Arkham Asylum ?