Well as you can see:
The World of Warcraft Armory
I'm geared to amlmost the exact same stats you gave in your post. I've only done this once before, but I'm pretty sure it's very reliant on having a good healer. I was able to do it without using cool downs excessively against warrior/hunter/mage lineup.
When I did it I started off with shieldwall (60% damage reduction 12sec) to give my healer a chance to ease into healing while i was rounding them up. Then I just stunned and shield blocked when I could to reduce damage.
I'd also say good dps is pretty helpful as it will really shorten the time required that you'd have to be tanking all 3 of them.