Hello Carol,
Your best bet as far as getting a replacement is to contact the manufacturer of the product, which is Caron. Here is the link on their website so you can request latch hook supplies for kits. (Just copy and paste this link into your web browser and it should come up for you.)
http://www.yarnspirations.com/latchhook/
I hope this helps! They should be able to get a replacement sheet out to you as soon as possible.
~Kristi @ ELH