Missing stroller seat

Question

I recently bought a used stroller thats missing the seats. Its an Avalon side-by-side stroller Style: A26TW235 (i found it at baby depot.com) the problem is the product is temporairly unavailable. I just wanted to know if there is a place that sells seats for strollers or is it even possible to buy missing pieces like this or do I have to just make one myself? ( lol is that possible??) well thanks for your help!