[Vwdiesel] Any tips for fused/rusted strut bolt?

[Doug Presny]

(1982 Rabbit Car) The top adjusting front strut bolt twisted off when
removing the nut.  After purchasing replacement specialty bolt, spent 2
hours attempting to rotate head off remaining bolt, using a punch from
the broken side, tapping with a hammer.  Finally twisted off the head of
the bolt.  Removed the old strut.  I am assuming the only approach I
have to remove the section of the bolt fused/rusted in the hole is to
drill it out with progressively larger bits.  If anyone has alternate
method to try, I would appreciate the tip.  I have only a hand propane
torch, but have not used it for fear I will create another unknown
problem. 

Thanks - Doug