Pretty much any jewellery store will sell them, in my area we have a store called "equip" and last week I saw them there :) if you have looked every were from one then you might have to buy it online, boohoo.com have some I believe and they have free shipping to Australia! and when I ordered some jewellery from there arrived quite quick actually, also eBay is another option. And if you cant find one online either ( which I doubt would happen) you may have to make one like Mabe said.
You can make your own with ribbon, and a costume clip on earring.
