You didn't say but I guess they cut across the top so that you need to stretch the door top? When mine was done the windshield posts were layed back so the door tops just came straight down. Anyway, on my '46 the inside door panels just unscrew and there is another set of screws that hold the window regulator to a cross brace. The whole thing comes out with the brace. The windows just dropped right down with the little plastic wheels in a channel that can be worked around to let the glass and frame come out as well. Once you get into it you'll see it's pretty simple. I don't have a source for frames as my windshield is glued in.
I don't know if the picture will help, it was when the door bottom was being replaced, but the regulator brace is at the top.
Hope it all works out!!