sheared bolt

Ive sheared one of the rear wishbone mounting bolts off on the passenger side, any advise on how to get the remainder of the bolt out would be gratefully recieved.

Ive found the holes in the floor under the carpet and made one slightly larger to improve access but still cant figure out how to get it out.  

only way to get it off is to drill it out  

hth

Bugger! was hoping not to have to do that.oh well.