I am trying to repair my mate's G1 Jetfire. The screw with a built in washer came out and the arm came off. There was also a spring which is stiff but with only about two turns it it.

I have the little black ratchet circle from the arm.

I have included the photo below of what I need which is still on the left arm. My question is where is a good place to look for these kinds of springs? I don't think Bunnings will be much help.