Most likely it's not going to go up much. You might be able to install an updated
driver from ATI and get it to increase just a little bit. It's a laptop and those video cards aren't powerhouses.
I wouldn't worry much about this...the WEI is pretty much meaningless. If it makes you feel any better, my work laptop which runs Windows 7 great only scores a 3.4. 5.9 for CPU, 5.9 for memory, 3.4 for aero graphics, 5.3 for gaming graphics and 5.9 for the hard drive.
My specs are Dell E6400, Intel Core 2 Duo P8600 at 2.4Ghz, 4GB of RAM, 160GB Seagate Momentus 7200.3 7200RPM hard drive.