You won't see any kind of greatly increased performance leap by putting a newer faster cpu in (that's if your mobo supports it in the first place), the single biggest and best upgrade you can perform is adding extra memory. A newer or faster cpu isn't going to get the kind of performance i think your after since your even considering replacing it.
If you really want to see what fsb your cpu has download and run cpu-z from
or check in the bios
and some steps on "how to" click here
You risk a very heavy paperweight!!
Seriously though... reconsider your options, this is one area i have come a cropper on and believe me the repair costs outweighed the cost of a new laptop :o(