Umm... I let Donald and Goofy kick the crap out of Ursula, load myself up with Elixirs and place myself in front of the cauldron and cast magic on it until ursula goes all *Why! WHY!!!!* You're just supposed to concentrate on the cauldron, it's how the battle is won ^_^ takes three minutes tops to beat her at this spot ... at level 46. ^_^ ok maybe 5 but I was busy avoiding dying. You WILL get killed once or twice this way but that's why you load your buddies with Hi-Potions or the three way potion thing... forget what it's called. The fight that is a pain in the arse is the Giant version of Ursula she suxs! *dies* I never even bother to LOOK at Ursula, just concentrate on the cauldron, you waste magic if you go after Ursula cause the pot is the key! err WOoT!1!!!11!

EDIT: and that's in MASTER mode ^_^