In general, MMO's are very processor-dependent. If you look at your Task Manager (Ctrl + Shift + Esc) while running the game, you'll see that it is taking up a high amount of processor power and memory. That being said, you wouldn't be too far off from manageable. 2.39 Ghz is certainly on the low-side for this generation, at least 2.9 or higher would be sufficient. 4GB RAM is ok, but 6-8 would be preferred, and RAM is fairly cheap now, even for laptops. Unless of course, you're out of space for more sticks. And your GPU, you can get away with a Gtx 560M, probably lower and be ok.

You can buy a laptop with these specs for ~$800. I'd recommend buying or building a desktop if you have the space for it, as you can probably get that for closer to $500 or less.