That Atomic SL-11 is with a Neox 6.14 correct? if it is? ScotsSkier is right, its one piece, and its not uncommon for those brakes to break. Working in the shop, from time to time, I do have a few of those come through the doors. The best thing is to take it to an Authorized Atomic dealer and see if they can get an RA# to either send your bindings back, but since the skis are at least 8 years old? they are probably out of warranty, so they may not be able to help, but if its just that brake? then they should be able to just send out that part. I've called Atomic before, and since at the time we were not an Authorized dealer they wouldn't talk to us, they told me to send my customer to an Authorized dealer instead, in which I did, but could of taken care of the issue here instead of sending the customer all over town to find a dealer.
Someone else mentioned finding those skis on Ebay, which I have seen quite a few on there. So if you want to just replace the whole binding? that may be an option, or get one off of Ebay and have another SL-11 as a backup.