Any competent body shop can repair that dent, can scan and match the paint, and the decals are available from Honda. I just had a much larger dent repaired on mine. The only issues we had was removing the tank which is a bit of a pain. And the tank is made of very thin metal, so when they removed the welded pulling studs, they would pull holes in the tank which had to be welded back up. But in the end, it turned out nice and a lot cheaper than a new tank.
And yes, the guy that hit your bike and knocked it into the post damaging it should pick up the repair tab. He damaged your bike and is responsible. Couldn't he turn it in to his insurance? That's how it would work here in the states.