It doesn't use the car key. There is a special key. Mine was in the glove compartment. You may have to call the Buick dealership in your area if you don't have the special key. (Mine was made of green plastic).
There is a tool that came with the car. It is T shaped and it has an eliptical end. Pop the center of the hub off and the insert the eliptical end and twist. This will let the hub free.
Depends on the type of lock, If its a common mortice lock you may be able to work it out with a screwdriver but if it has been jammed into a cylinder lock as an act of vandalism then the only real...