From your pic it seems that you just need to drill your bumper with the bolt pattern of the winch?
It is a custom made bumper by me but at the time I built it I did not think I would get a winch...famous last words right?
Anyway, the top of the bumper is only 3 inches so it is too narrow for a winch at the moment. I can either buy a winch mounting plate and modify it slightly to make it a complete bolt on deal or I can take my bumper off and modify it to accommodate a winch by doing a little cutting and welding in a winch tray.
Another option is to just weld in a square tube for a hitch and use one of those winch cradles. I could use it on front or back that way. And also I keep it stored out of the weather when not in use.