Not a bad idea. I also hear Cheliax is pretty lax in their moral outlook.
Uuuunfortunately, An needs to hunt down and wipe out whoever is manipulating her sister. Because you don't secure an ancient, hidden fortress that houses a barghest, a transmutation chamber, an unhinged wizard from the Pathfinder Society (Lyrie), and a key to open said prison just by having freaky dreams of Lamashtu. That takes money and connections. And it's more than a lilttle suspicious that, when questioned about said benefactors, Nualia immediately refused to tell An-Nur and said in no uncertain terms that particular line of questioning would lead to a shallow grave.
At this point, I'm not so sure Nualia even really knows who/what they are.
Forget about her, Kolto. ;( Find yourself a pretty, simple wench to take to bed at night. Spies don't have happy endings.