kdc-w7534u control knob/button not working?

I have a faceplate for the Kenwood car cd player model number KDC-W7534U.
The "control knob" for changing tracks and going up and down folders does not work fully anymore.
I believe the pastic connector/clip inside which allows the lift, right, up and down movement is broken.

At the moment I am able to fast forward to the next track or go down a folder, but cannot go up a folder or rewind (so if i push the control knob left or up - nothing happens and it doesn't click like it does when i forward or go down a folder).

I was wondering if you could help me as to what parts I need to fix the problem, how much they cost and how to do it?

Any help would be much appreciated!!

Fez
October 2009