ok. i think that's bill briegers puch mk2. i could be mistaken. it might be a erin's puch maxi (but i thought that had a smaller seat).
don't worry about it missing parts. puchs are very very verycommon. even w/ different types of mopeds, they essentially have the exact same engine. the only nonuniversal parts might be body parts. levers, engine parts, switches, all that are completely standard. you can get parts for that bike and get it running w/o any problems.
call handy bikes and ask for bj to get parts. they ship nationwide. we always go through them. also, check out the mopedjunkyard.com and see what parts they might have for you that you'll need. even if there aren't pictures of the part, just email and ask for them. they will know (either place) and help you out.
fixing mopeds seems difficult ... but it's not. you can get it down pretty quickly. always feel free to come down to kzoo and look for people at the deceptiplex who can help. i don't know much about puch (i have a minarelli engine), but we have lots of members who do.