You try replacing the ignition switch inside the steering column? I know that's separate from the cylinder. I don't think it cost much more than $30 from autozone for it. There's probably some linkage in there hanging up.
I don't know what steps you followed. But, sometimes if you try wiggling the steeriing column it will free the locked column. to better explain----- 1) key in ignition 2) wiggle steering column and try unlocking the ignition. Most times works. If you have a problem at that point I would suggust seeing a friend that is a mechanic and have him troubleshoot it for you.