How to overclock my gpu and cpu for Lenovo z51-70?

My amd catlyst drivers don't have option to overdrive and and i can't even edit the bios. Can someone help in this regard?

Most "name brand" computers are unable to overclock. The BIOS is locked to prevent overclocking.

That is a laptop. The cooling and power inside it are already at maximum. If you want higher performance and ability to overclock, get a desktop box.
http://www.tomshardware.com/answers/id-2310126/overclock-lenovo-t420.html
http://www.tomsguide.com/answers/id-2686648/update-lenovo-y50.html