Mine just broke too, the blade was worn enough that it detached from the assembly.
I think you need to replace just the blade but not the entire assembly. I was just being lazy and figured it's in the manual but haven't checked yet. Keep us posted. It would be insane if you had to go to the dealer to replace a wiper blade!
I called all of my local dealers and nobody had one in stock. The guy at Manhattan Mazda (the Ford/Mazda factory dealership) told me that he had never even seen one before. I just ordered one from Jim Click Mazda Parts. It was less than $20 with shipping. Hopefully it will get here soon.
Yes, it is a dealer item only. That is if you want it to match.
Yes, you MUST remove the pivot cover. Then the wiper blade comes off easy.
Now for the possible alternative source. The 2012 Focus looks like it uses the exact same wiper blade. So maybe it's cheaper through the Ford dealer? I haven't checked myself but it is a possible option.