Welcome to the QuiltingBoard! This machine uses the New Home rotary system and takes New Home (or Free Westinghouse) rotary bobbins. And yes they are hard to find. Slightly less hard to find are the needles: CC1221 or Boye 2 1/2 or Kenmore 49.
A quick search on ebay shows nothing. You can try etsy also. I do not like to refer people away from this forum, but over on victoriansweatshop.com there's a classified section and a "wanted" subsection where you could post a request.