Working with signup registration data?

I am building a website where the visitors should to signup for different courses. The registration form contains a lot of custom fields, 12 to be more precise (name, address, phone, dog name, etc.).

An administrator should be able to work with the registration data in several ways, e.g.:
- generate an invoice with data from registration.
- generate a custom list with some of the data from all the participants on that course.

Which is the best way to use the information from the signup process in another module or content type?

Or is it a better idea to build a custom module instead of using signup if you have these type of needs?

Regards,
Mattias Eriksson
Enwebb