Hello and Congratulations on a SUPER machine! You should be able to get feet and cams on ebay. My Mom purchased the 158.1802 for my 13th birthday many many moons ago. I use it alot! Just love this machine!
The best thing to do is to find the whole box with all of the attachments and the basic cams. I've been searching for years to complete the alphabet cams. You might expect to pay around $50. on ebay for this box.