( bottlenecked gpu ) how to overclock amd cpu?

[punkuser3]

I have amd athlon II X2 260. It bottlenecks my graphics card while playing games like dota. So i want to overclock it. i have a motherboard of biostar N68S3B.

 

[RARRAF]

http://www.amd.com/en-us/innovations/software-technologies/technologies-gaming/over-drive