Maybe you or your hubby could cut a piece of plywood to fit the window space.
I had the same situation in my old house. Planning on selling, so I didn't want to start drilling holes and hanging permanent ducting. These pics are of my short-term solution at the old house. A piece of plywood cut to size, edged with weather stripping. Braun wall fan from Grainger and speed controller mounted. Even a little hole drilled for the fuel line. When I was done, I could just pop the plywood right out, and close the window. Flex ducting inside from fan to torch.
Since the propane was left in the bushes in the front of the house all the time, I eventually had to get a box to put the propane in. Both for safety and for protection against the really cold weather.
