I would not bother. It is likely your RAM along with having a 32-bit operating system is causing your biggest bottleneck.
You did not say how much RAM you have, but the 32-bit OS limits the maximum to 4GB but even then, only ~3.2GB will be usable due to the way 32-bit operating systems map hardware memory.
But worse is a large chunk of your RAM is likely dedicated to graphics processing giving your OS even less RAM to use. That alone is a bottle neck but it also means the OS is forced to use the Page File on your hard drive much more often creating yet another bottle neck.
Just upgrading to 64-bit Windows 10 will give your system back that RAM that was taken for mapping. That is, Windows will be able to use the full 4GB (less what is used for graphics).
According to
these specs, it looks like that notebook will support up to 16,384MB (16GB) of DDR3 1333MHz RAM.
If me, I would replace your current RAM and install a 8GB stick, then upgrade to 64-bit Windows. I am sure you will see a much greater performance boost that way instead of upgrading your CPU and then straddling it with 4GB and a 32-bit OS.
Also note that many notebooks, to reduce weight, notebook thickness, and costs, use surface mount processors - that is, the CPU is soldered directly to the motherboard (not inserted in socket) and cannot be replaced.