Congrats Mike, that is a nice start.
Classic Arcades sells the complete drop target set for Paragon, and you can find them on eBay. Marco Specialties and other stores might sell them individually so you could possibly add it to a bigger parts order from them.
My guess is that some of the hardware may be missing so I suggest that you upload a picture or two when you can as it will allow for the group to make suggestions and guide you through repairs.