Wow! That's a good bit of carnage. I've dealt with something like this before, albeit on a small block Chevy. I managed to extract the old crank pulley bolt using a slew of extractor bits, regular drill bits, a dremel, thread chase, and A LOT of patience. it took me and a guy I work with about 7 hours of consistent work, and I would never have done it had the car not needed to make an event in the morning. The thing that really makes your situation bad is the fact that the woodruff key slot is fubar. You're never going to be able to time that engine properly even if you do manage to get the old bolt out.
You have two options at this point: get a new crank or get a new short block.
If you're good enough to do the work, get a crank and have it machined. It'll be cheaper, but only if you assemble.
If you've never built a bottom end and/or you need someone else to do the work for you, a used short block will probably be cheaper. Or you can get brave and learn on this one. But that's about the only two options you've got in this situation.
