What part is this and where can I get it?

After the Power and Lock Button was not working anymore (does not 'klick' anymore) i decided to disassemble my iPhone to take a closer look because Apple said it cost about 200 Euro to repair and thats too much.

So i end up with this here:

http://www.picfront.org/d/8AI3

As you might see, the button itself is ok but the other 'thing' is broken.

i mean this part here

iPhone 4 Power & Lock Button Replacement

The part on Step 23.

So can anyone tell my which part this is and where i can get it?

(sry for my bad english, im from Germany :P )

Thank you.