You COULD drop the game to Casual (if it isn't already). Or, head back to the village, Dr. Needleman is on the 2nd floor of the Tavern and he sells potions. If he's all out you can go to the alchemist and make some pots... if you haven't done that yet, I'll give you two words that'll help you find it:
Mindread
Windmill
Aside from that, level 13 is a BIT low. I was 15 for the encounter - have you thoroughly explored Broken Valley?
