the door is probably a generic popup door. i would take it to a popup dealer and see if they can order a replacement.
i would also join Popup Explorer, probably the most active popup owners website.
someone there might have a better suggestion.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC