I would measure the diameter of the plastic overlay and order a circle cutter online. Their website indicates a lifetime guarantee.
I also have Mirror Back Badge parts posted. You can check Badge-A-Minit's website for more information. This item is in the category "Crafts\Multi-Purpose Craft Supplies\Crafting Tools\Badge/ Button Makers". The seller is "hikaneohe" and is located in this country: US.
This item can be shipped to United States.