Strange! How comes you needed so many potions? I used a singing sword, though, so that ______ didn't even had the time to aim: I entered and used Flash attack (which somehow makes me think of Nightcrawer <img src="/ubbthreads/images/graemlins/alien.gif" alt="" />) and she's dead after several hits.
I used -half- or less of the potions I brought. Josephina is much harder to fight as a mage, because even magic attacks at level 5 do mere fractions of what a sword does to her.