Sorry to hear about the damage to your bike. There are a lot of rotten people in the world.

Place your lock around your rear wheel, directly behind the seat tube and lock to a thick, beefy steel post set in concrete. NEVER (repeat...NEVER) put a u-lock around the seat tube or any other part of your frame. A dumb crook will attempt to use the frame of your bike as a lever to snap the u-lock. That "lift and twist" method works when a flimsy Wal-Mart lock is on a 40 pound Wal-Mart bike. But, when a Kryptonite or OnGuard u-lock is on a high quality frame, the frame will twist and bend.