Yeah most laptops ship with pretty low-clocked CPUs, it's pretty normal. It's pretty hard to upgrade the processor really and probably not worth the money or time doing because once you've upgraded the CPU the performance difference will likely be negligible to say the least. :/
I'd say your GPU is at fault here. Just because it has 256MB of V-RAM does not make it a strong card. For example, a 1GB GTX 560 will smash a 1GB GT 440 for example. It's about the GPU power itself, not the amount of RAM the GPU has.