Broken Rear Derailer Hanger

[cobi]

Bought a 2008 Trail X2 this spring to see if I wanted to get back into biking. I'm loving it! I'm already trying to decide what I want to buy next! Was hoping to get through this season on this bike then turn it into a commuter when I upgrade.

Anyway, was riding yesterday and had some problems so I took it into the shop and he said the rear hanger was bent. Weird since it was a pretty easy trail and I don't remember hitting any rocks or anything like that. Anyway he used some tool to bend it back and I was on my way.

Decided to go biking this morning and of course hit a rock that swung up and hit the rear derailer. I knew instantly it was bent again, because the shifting problems returned. Decided to try to finish the ride since I could shift OK as long as I didn't use "1" on the rear. "2" was actually shifting it onto the biggest ring. Anyway got a few miles further and the whole thing broke. Thankfully it was only like a mile mostly downhill to get out, so I tied it up and coasted & walked it out.

The bike shop isn't open today, but my question is....... will they have the part in stock. Is that a common item to keep around?

I've looked online and can't seem to find the exact looking one. This site seemed to have a big selection for the Jamis but none look quite right to me.
http://www.derailleurhanger.com/jamis.htm

It's probably closest to #31 but I don't think that's it.

Also does anyone carry a spare on the trail? And is this a part I can/should upgrade to a stronger one?

[cobi]

Bike shop had an aftermarket one that will work. Thanks anyways.