It all depends on what motherboard is inside your laptop. You can find out easily enough by downloading a small free utility called "CPUZ" - run this and you will find out a whole load of information on your laptop regarding the CPU and mobo, along with RAM and chipset.
The motherboard tab should tell you the make and model - which you can check on the manufacturers website.
Now for the bad news. Upgrading anything other than the RAM and HDD on a laptop requires the case to be taken apart - which can be tricky even to the best of PC builders.
If you are feeling brave and can find a CPU to upgrade your laptop then I wish you good luck.