Electrical's and Plumbing experts Showerss.... Pleaseeee!?

Hi! I have a really old Triton shower (it is 7.2kw) And i'm planning to change it to a Triton Electric 9.5Kw Shower. Will i have to change the cables? If so will it cost a lot of money as i am a bit tight on money at the moment! Thankyou In Advance!