[BilLster]

have someone weld a bolt to it for you (portable welder) heat up the area aound the broken bolt but try not to heat the bolt directly .

if this doesnt work they have drill bit's secialy designed for people like you and me that this happens to except i spent a week drilling and trying to get one out before i found out .
it looks like a trident thing on the end it fits over the broken dolt and the drill bit is then centered and you slowly drill the bolt out untill you can get a easy out into it .

or you screw it up so bad that you have to drill everything out re tap and use a bigger bolt.

I feel for you been there done that .
oh yeah soak it in liquid wrench first