Dragon Age Origins - Flemeth's Grimoire quest?

I've beaten the blight in DAO and now I'm doing DLC quests. I gave Morrigan Flemeth's Grimoire sometime before finishing the game, and now Morrigan has asked me to go kill her mother. But I can't seem to travel anywhere except where the DLC quests are, and the quest isn't even listed in my current quests menu! Can I still do this quest?