I'm not to familiar with the bolts used to hold this windshield, but I'm assuming these would only be a 1/4" sized bolt roughly???
Could you not purchase an easy out drill bit to do this yourself? Like I said, I'm not sure what's holding things together here, but if you can I would suggest drilling on top of the bolt head to fit an easy out bolt/screw extractor bit.. just a thought..
You can usually by them in lets say a set of 3 different sizes for future situations..