The aircraft departed Deer Lake, Newfoundland and Labrador, and upon selecting gear up, the hydraulic light and the annunciator came on. The captain immediately shut the hydraulic pump off as per memory checks. After completing the checklist it was determined that they had a hydraulic leak in the system. The main accumulator still had some fluid so they decided to bypass Gander and continue on to St. John’s where the weather was better. Landing was normal. The captain had some steering and soft brakes. The captain decided to taxi the aircraft onto the ramp area. He feathered the propeller about 150 feet from the hangar. The forward thrust from the props going into feather gave the aircraft some forward momentum. With the slight downgrade the aircraft rolled until it hit Hangar 3. The captain had no brakes or steering. There is substantial damage to the nose cone area. The hydraulic leak was caused by the failure of a hydraulic swivel in the right hand landing gear.