Help! Wiper pivot stud broken

Thanks for the advise guys. The picture that Tony presented is exactly what I am facing. Will probably wait until the weekend to tackle it. I am thinking that I could maybe get the correct size bolt and put it in from the pivot shaft hole after the stud is drilled out (it will be tricky) then tack weld on the bottom side of the cowl. Should only be a once is lifetime repair.
be careful - IIRC the base sits flush to the dash - anything in the way will cause it skew and interfere with proper operation