Since key is in the ignition barrel I guess you should be able to get the lock itself out of the barrel. To replace it or get a better grip/view/leverage.
Removing the lid where it says "lock, on, off" etc on by twisting gently either counterclockwise or clockwise (Can't remember which direction), you'll remove the lid. Then there's a trick using a hex key in a small hole on the back of the barrel to get to a lock which you can push in to release the barrel.
Some youtube-videoes out there explaining the process better .. ;ol;