Not a dumb question at all sunshine-it's happened to me many times before, and again today.
open your ended listing, on another page, open ebay.ca, and proceed to sell...copy and paste all your info-title, description, even pics (which have to be first saved in your pics folder and then re attached to your .ca listing)...it seems like a long headache, but after the first and second one, it gets much quicker. i know its long, but i'm afraid that's the only way...unless anyone knows of a different way, short of creating all new listings. i emailed ebay a while back regarding this issue, and they said there was no easy 'direct' way of transferring over files from .com to .ca...
good luck..!
Kat