All of the pictures of that moped seem to indicate a Franco Morini engine with a Delorto Sha 14:12 carburator. The carb top, plastic airbox, and clamp, if in stock, ought to be available at treatland.tv fairly cheap. To get the correct petcock, take the gas tank to a local hardware store and determine the proper thread, then get the corresponding petcock, again from the above mentioned website. As for kill switch, it's probably on that site as well.
Get one that looks pretty close to what you need. I doubt you will spend any more than $50 for those items, with shipping, wherever you find them.