I overclock my laptop using the nvidia control panel. This is only possible because I have an nforce chipset. Laptop's usually have no overclocking options in the Bios so you are limited to whatever software tools you can find that will work (I tried many software tools and most of them were completely useless, but you might get lucky).
I was unable to overclock my GPU at all, but I did manage to push the CPU for an extra 400 mhz.