Arwena, which curse did you take? There are 2: the withering curse from the mage path (enemies have resistances against it) and the survivor's curse from the mage path ( enemies have NO resistance against it)
If you take the survivor curse (several clicks to get her really down - her spiritual resistance is pretty high), Josie should have a white spot on her body this symbol shows, she's cursed. Then simply hit the pause button, choose the polymorph spell in peace and quiet and polymorph her.
You don't have to touch her, it's a long distance spell, but you should target her, it's no area spell.