Those are made from pieces.
The masks can be found anywhere.
Batman is wearing a Bat belt buckle (try Hot Topic) on a harness (local leather store). While there look for the leather jockstrap/thong he is wearing.
The cowl and gloves are probably part of a bagged costume.
Robins mask and insignia are probably ALSO from a bagged costume. Indeed the Robin top might just be a crop of the bag costume because of the green sleeves, which is kinda an offical thing.
NOW... Robin tends to either wear green or red "trunks" not black leather ones, but the shorts in the picture and the cuffs worn by Robin could be found at the local leather store.
Best of luck buddy! PERSONALLY... i think a creepy but hot Joker would be WAY cool.
White body paint, purple speedos and a purple trench coat with a squirting flower, green hair, and just because you're the Joker, green striped tube socks.
I was Gemini one year, from Batdance, the half Prince/Batman half Joker character, but I had the costume made and got half a head of green weave done for it. I wish i had pics of it, but it was before the world had digital cameras.