that is because your videocard is built into the motherboard & is sharing the main ram of 64megs. 64 + 448 = 512. what does it say for the name of the videocard in the display tab in dxdiag??
it doesnt have a name all it has is this Manufator:N/A Chip Type:N/A DAC Type:N/A Approx. Total Memory:N/A Current Display mode:1024 x 768(32 bit) (1 Hz) and Moniter:
check this link https://support.ati.com/ics/support/default.asp?deptID=894&task=knowledge&questionID=640
i think so but i don't work with laptops much & depends if you can put a new videocard in your laptop.
i don't know as all laptops are different. check your laptop manual for that info or the place you bought the laptop from