Stay as a prot spec as it will help with damage reduction and tons of AOE DPS. Start swapping prot gear for ret gear w/o loosing your crit immune. Even a spell caster item or 2 to boost your int pool helps speed things up. Seal of Command and Reckoning are your friends.

This is pretty easy to do if you have ICC gear and you will mow heroics. You dont need 52k hp in a heroic or icc for that matter.