Hi - The longer you are here on the Forums, the more familiar you will become to Inland RV and Andy. They should have your clips, and you can go to Andys Profile in the Members list to get a direct link to Inland RV.
We too are in the process of replacing clips for our Argosy curtains and use what is called a "G" clip (looks like a G when turned to the side). Inland is having a sale thru Sept. and several styles of clips are on special right now, ours being about .35 a clip. Inlands site shows pictures of most of the sale items by going to the PARTS page and scrolling till you find what you are looking for.
I have seen reference here on the Forum to replacement curtains. Some make their own, but seems there is a place that will custom make. You might try the Search button with "Curtains", or wait a while and someone else may reply here with link. Good luck... Leigh