Drilling that bolt out is going to be a real PITA. Can you even get a drill in there? You may have to buy a small right hand drill fro access. I don't have my car with me, so I can't go out and look.
Use a center punch, and make a big dent with multiple taps. Start with a small bit, like 1/8" or so. Go slow, go straight, and use plenty of
oil.
When the hole is big enough, tap in a course rat tail file. Turn it out with a pair of vice grips. Be sure and use plenty of penetrating
oil, like PB Blaster.
It will probably be easier to push it back out the way it came in. There's probably a burr where it broke, and that burr will hang up on the threads.