Hi, welcome to IRV2.
You can search for a used bumper by researching the various salvage yards. Put "RV Salvage" in your search engine (like Google etc.) Here's an example.
Sometimes a body shop or muffler shop can straighten the metal tube with a hydraulic tube straightener. Check around locally.
Good luck. I'm sure someone more familiar with the Minnie Winnie bumper will be along soon.
Thanks for joining us here. Great bunch of people.