Well, this is kinda late, you may have already found a solution.
The whole key to easy replacement of the ignition lock cylinder is whether the switch can be turned ON. If it's jammed in the off position, then it must be totally taken apart, super-hard steel drilled out, etc. If it is still ON or can be juggled/lubricated enough to get it to turn one more time, then it gets pretty easy. There are several tutorials herein on how to make a little steel rod (a coat hanger works for some) to slide in the slot on the switch when it is turned ON and just pop the switch out.
I've found they vary by year, but do some research here and see if you can fine the write-up on your specific model. For my '91 you take a coat hanger and grind an angle in the end, slide it into a slot alongside the key and work it down to release a little lever. Takes a bit of fiddling, but it works. Buy a new lock cylinder and take a look at it, gets easy to understand then.

Good luck.