I didn't mean to imply that you need to replace the vent with the exact same unit. That is essentially a "new work" device, like a window with a nailing flange.
There are "old work" vents that have a bezel so they mount to the outside of the siding. If you can't match the color, painting the vent is an option.
Hopefully it will take you longer to climb the ladder than to repair the vent. ;-)