There are a few challenges to attempting to upgrade your processor. The main one is that the CPU is soldered onto the motherboard, the process to replace it is called reballing. Reballing requires specialized equipment and quite a bit of time (there are vids on YouTube that show what is involved, I think it's fascinating). Then there is the bigger question of supported CPU's and/or BIOS modifications, Toshiba is quite 'tight-lipped' about that kind of stuff - there are ways to overcome that but I think at this point you may see why I say replacement is the way to go rather than upgrade.
One thing to try (which may make upgrade feasible), contact Toshiba and find out what kind of CPU upgrade information they can give you for your model...