If a rod building supply outlet doesn't have it try NET Craft. That's were I get mine. You can buy by the each.
The grommet is available from any ACE Hardware, Do It Best hardware or Lowes. They are usually located in the speciality pull out drawers in the nut and bolt sections. If you do a search on this site you will find a posting with good pictures. I think it was about 2 yrs ago.