Thanks
You can either get the Meguiars heavy duty headlight restoration kit which comes with all the stuff you need, costs around $65: http://www.meguiars.com/en/automotive/products/g3000-heavy-duty-headlight-restoration-kit/
OR you can buy http://www.meguiars.com/en/automotive/products/g17110-headlight-protectant/ separately
I had bits and pieces from various kits with sanding and buffing pads which basically made up the Meguiars kit, you'll end up with the same results if you just buy the kit, you'll be able to use it more than once.
If you only want to get the protectant though here it is on ebay: http://www.ebay.com.au/itm/Meguiars-G17110-Headlight-Protectant-10-oz-/140709679655?pt=Motors_Car_Truck_Parts_Accessories&hash=item20c2f35227&vxp=mtr
Might be lucky and find it on the shelf at autobarn. You'll definitely find the whole kit there though.