I read the Amazon website and someone who has it running on a 3 ghz Pentium with 1 gig of RAM has the same problem. Hes altered what game settings he can to lower the graphics but still says it lags.
Thats all you can do. Alter the game settings in the graphics to a lower level and see what happens.
I suppose it must need really powerful hardware to run properly and you might struggle with you laptop I'm afraid.