You need a Singer cord set, # SCE123 on the Sew Classic website, $9.99. You need your own plug and foot control, which you have. If you need a new FC, you can buy one from that site, too.
Cindy Peters, at Stitchesintime has used parts for many brands of vintage sewing machines. She's the "Captainette" of Treadleon. If you can't find her with a Google search, get back here and I'll hunt up her email. I might have the screw you need in my stash.....I'll go look after breakfast.