Meet Albrecht in the central Forest of Runes. After fighting the goblins with him, you'll get the quest.
There is a goblin shaman north of the meeting point with Albrecht. You get the ring by defeating this enemy. Here are two strategies allowing to beat the goblin shaman (and the three goblins accompanying him) without removing Aura's collar:
You still get the ring if you beat the shaman before meeting Albrecht.
If you examine the ring in your inventory, you can get one ether. Doing so, will break the ring, though.
To finish the quest, go talk to Albrecht in the Boar Hut. If you bring the ring intact, you complete the quest. If you broke the ring, you will fail the quest.