HSF stand for Heatsink Fan: Its the fan that sits directly above your CPU, also called an "active heatsink" because it has moving parts, there is also the "passive heatsink", which is the little piece of metal that the fan sits on, all in an effort to disapate heat, and keep your CPU cool.
2200 is pretty good... I would say stake small steps, and whenever it gets unstable, thats when you quit...seeing as stability went out the window at 2200, you would leave it there.
A water cooling system is a little extensive dont you think? The things can cost upwards of 300+ dollars, all to get maybe an extra few hundred mgz...With processors at the speeds they are now a days it hardly seems necessary. But to each his own I guess
Heres some very helpful links:
www.helpoverclocking.com
www.ocwarehouse.com