I have a pretty similar laptop (a bit older, but otherwise identical) and it runs FFXI all right, which means it'll probably handle WoW all right as well.
However, the bottleneck is definitely going to be that hard drive. 5400 RPM is older technology and it just can't keep up with your processor. It used to be that processors and video cards RAM and motherboard bridges were the bottlenecks in any given system, but not any more. I'm actually going to replace the HHD in my laptop with a solid state drive, as well as add an SSD to my main workstation as my OS drive. Solid state is the Formula 1 race car to a standard 7200 RPM hard drive's Honda Accord. And the 7200 RPM makes that 5400 RPM look like a 1978 Gremlin.