Congratulations, Laurie! Isn't it exciting?
You can download a manual from ISMACS here:
http://www.ismacs.net/singer_sewing_...e-manuals.html. The 221K manual is from 1951, so it should match your machine well. If you do a Google search for "featherweight parts", you'll be able to find a number of suppliers.
Good luck; I've found people on this board very friendly, so if you need help, just ask!