try a craftsman 'bolt out' or similar extractor. i've had some seriously messed up bolts on my 3rd gen due to rust, and these things have been a life saver twice now

 

Go to a local sears.

http://www.sears.com/shc/s/p_10153_12605_00934506000P

this isn't extactly what I have, but close. I'm sure these will work.

 

i bought something similar, but i was having problems rounding it off with the extractor.. tommorow im going to just hammer it on good... i just gotta keep at it

 

try this, when attempting to use an extractor, first drill a very small hole to get it centered perfectly, then go with a bigger bit, sometimes a time or two or three, the most important thing is to get it centered perfectly the first time and a deep enough hole