All in one cable almost broken

I have a Thunderbolt Apple LED Cinema Display 27". The all in one cable is almost broken. I need to replace it.

But I believe apple already stop product the part, and last time I check in the store. They said I need bring my monitor to and they might or might not fix it.

Any one did this recently with Apple? How much they charge?

I also find the part online about $150. How can I do it myself?