I recently got Hircine′s Ring and I was under the impresion that I could use it to change into Werewolf form whenever I wanted, the thing is that I needed to be a werewolf on the first place to do so. I was looking foward to it turning into a werewolf without having to resort to the Companions, Dawnguard, mods or outright cheating in the console....but I guess I am out of luck. Any suggestions?

Joining the Companions and using console codes are the only ways of becoming a werewolf. Period.

Not sure why you mentioned Dawnguard, it does indeed introduce wild werewolves, but you can't contract lycanthropy from them.

Companions, console, or nothing.