Broke metal part that connects to locking mechanism

I purchased a patio door handle with a lock. The directions said to snap the metal peices to match my slide doors thickness (1.5"). While holding the metal bar and using sharp pliers I snapped too much resulting in a too short piece. I cannot find any other locking handles in stores. What is the metal that connects inside the locking mechanism called? I need to replace it on the side that has the key hole to unlock from outside. 

I'm not a handy person but I want to be. I may need to replace the whole thing but I'm hoping I only need to find the part to replace the too short one and make them both fit my slide doors 1.5" thickness.