Either has to be the switch or the wrong key. I'm pretty sure you would know if it was the wrong key.
If you get a new ignition switch, I can tell you how to change it. It really isn't to bad. Pull the covers off the steering column, the switch is sort of clamped on. You take a chisle and put slots in the top of the bolt heads and then just unscrew them and put the new switch on. Tighten up the new bolts until the heads break off and you are good to go.