Do a search for frame builders in your area. There's bound to be a few near Toronto.
I'm curious why you wanted to replace the headset. My experience with '70s vintage Raleigh headsets is that they are pretty darn tough. My main commuting bike is a 1972 Super Course with probably close to 35,000 miles on it and the headset cups and races are perfect. Likewise on my 1974 Competition.
Good luck.