Other than finding a nice used one, you're probably stuck. You might want to call HEARTBEAT CITY
(if you already haven't), and see who makes theirs. I believe they're all the same though.
When I was (MUCH) younger and repop parts weren't available, we used to go down to the 5 and dime (ask your parents), and get woodgrain shelf paper. There was one that was actually very close in appearance! It's probably no longer available, but you might try some of the home improvement stores or hobby stores in your area and see what they have in the way of contact paper and/or veneer.