Obviously you will need to replace the ignition tumbler. Please bear with me here.
Chances are you do not have the new part with you. I had a slightly different experience and decided to change the "electrical" part of the ignition switch. When I removed the ignition tumbler and compared the old with the new I discovered the new "electrical" part did not have the "locking" mechanism that secures the ignition switch to the ignition wiring.
If this is the case (because a previous owner has at some time already replaced the tumbler) with your car you may be able to unplug the electrical from the back of the switch tumbler and jump the appropriate pins.
Perhaps someone here can help you with the correct contacts. I do not know this information.
In the meantime, try this link to study what is involved in removing/replacing the stuck key problem...
http:
www.peachparts.com/shopforum/showthread.php?p=1065596
Good luck