many ways to go about this problem
remove plastic shroud from steering column
are you able to turn ignition to acc position if so there is a small hole near the top push a pin or similar into hole there is a ball in there holding switch into housing push it in and pull switch out at same time take switch to a locksmith for repair
if you cant turn switch suggest you get a locksmiths advice but maybe you are able to remove the broken screwdriver bit and get your key into lock enough for you to start car and drive to a locksmith
