Ben,
From your photo it just looks like your ball bearing and spring has popped out, causing your arm to just flop about. You can replace those quite easily. I have recently had to do the same thing. I have the measurements for the ball bearing and spring, just not with me. Let me know if you need them.
If, as Larry has asked, you've had something structural fail, then you'll need to replace it. However hold onto the washer and circlip, you will not find replacements for those. I have looked.
Rick.