Dropped on the zoom. How do I replace?

My camera was dropped and the zoom lens was buckled out of round. Everything else appears to be OK, but can not operate with this problem.

The damaged ring has this written on it….

NIKKOR 38X WIDE OPTICAL ZOOM ED VR

4.0-152mm 1:3-6.5

Can you tell me where I can get the replacement part and how do I replace this?