Kevin Fairchild

Help! I have noticed for some time now that my ignition switch has been trying to go out on my '82 SC. Well yesterday it finally happened. ..... It started several weeks ago. I would turn the key and nothing would happen. I could turn the key all the way to start, but nothing would happen. I would turn the key several times with no luck and then, like magic, the car would crank right up. Well this went on for a while until yesterday. I must have turned the key 50 times and still nothing. I am pretty sure it is the ignition switch (I recently got a new batery, cap, rotor, coil, checked all of the connections, etc. and the problem still persisted)but my questions are:
Will I have to replace the WHOLE ignition switch (including tumbler) or can I just replace the "switch"(BIG price difference)?
Has anyone performed this procedure before? How difficult is it?
Thanks in advance for the help.