I doubt you'd be able to find classroom materials for sale anywhere, since PTC or their training partners would likely rather have you go in for training or send someone on-site.
Best I can suggest is to look into online training for a few users and develop some of your own training material specific to what you do. I don't know how well that solution would fit into your time/budget constraints though. I've done similar things in the past and from experience, they take a lot of time, especially if you've never written training material before.