Sailrite.com has the rivets you want, and a new clew plate if you need one. If you are buying new rivets, get the tool to install them also.
I prefer to hand-stitch clew plates on to my jibs. More work as you need custom clew plates (we make them ourself), but you can easily see any wear and fix it before they break. Not a solution for you I am afraid, as you would need to install new reinforcement patches to take the thin thread instead of rivets.
If the clew plate has come loose, how old is this jib? Perhaps it is due for replacement anyway..