See if you can get on it with an angle drill and a reverse drill bit(NOT an extractor) -- and some PB Blaster or Aerokroil. Stay as perpendicular as you can; you might be able to spin it out.

I take it you don't have an AC unit in the way (yet); that's helpful.

Chase the threads before installing a new bolt to make sure it's still good to go.

Personally, I don't like leaving stuff like that hang unless it's to limp it home or to a shop.

http://www.walkablecommunities.org/

Democracy is two wolves and a lamb voting on what to have for dinner. Liberty is a well-armed lamb contesting the vote.

**ubi apis- ibi salus**