Welcome to the forum Bob. You haven't filled in your profile so we don't know anything about you. There might be an aftermarket parts dealer near you.
Most of the things we buy are either from eBay or off a web site, but as hooligan has said you might want to check out some cruisers with the parts your thinking of buying and then look around for all the places that sell them and other parts like them. For instance, if you see some taillights that you like, there's probably 2 dozen different kinds of tails that are available on different sites. Here's a couple sites to get you started ....
www.RaceandStreet.com
Cruiser Motor Sports
Mile High PT's
Revel Enterprises -- PT Cruiser Parts and PT Cruiser Accessories Home Page