id definitely consider doing some of the film to hold yourself over. its not the greatest looking stuff, but who cares. it will save you hundreds just dealing with it the rest of this year.

that or even get some quality full coverage curtains for the original windows, and getting in the habit of keeping your blinds closed when you arent in the room.

we have a pellet stove, but we can literally cut the amount of fuel we burn in half by keeping blinds shut vs open.

i know you didnt ask for this advice, but it might help you out.