Hjelp: Uppgradate Toshiba Satellite C670 !?!?

The Only thing you can spend money on that is to upgrade your Ram memory and to replace your mechanical Harddrive to a SSD.
That notebook check page you listed doesn´t show your specific system so im just guessing on the ssd and ram, But it´s not worth spending any money to replace the CPU for more juice. Atleast thats my opinion.