Do a little research. what you're looking for is an epoxy that is made just for the type of plastic that the bumper is made of.
Repair from the BACK so you have minimal body work to do on the finished side.
JB Weld may even make an epoxy just for plastic bumpers, if not, check with an autobody repair supply company....
Primer: you can get primer with what they call a flex agent...this allows it to flex in the heat and shrink in the cold without cracking, as the plastic does alot of moving around in different temps.
I have repaired plenty of motorcycle side covers and if you don't find the right epoxy, it will just break again...
I would back up your repair with Gorilla Glue Tape after you have finished with the epoxy. That tape is like a weather resistant super duper duct tape.
Depending on how well your repair goes, you may not even need much in the way of paint.
Incidentally, the best way to repair that damage is to take the bumper off and do your work on a table.
Lastly, collect any loose pieces of bumper NOW so you have all the pieces of the puzzle for when you do are ready to do the repair.
Good luck with it and post pics as you go along...