Jynx and Swinub/Piloswine are you best bets for Claire. She is a dragon trainer so all your other elemental Pokemon are going to do about 1/2 damage to hers. Dragons are weak to other Dragons and to Ice so picking up ice pokemon or two would be good for the fight. Unfortunately the only real place to get ice is right before the gym so you will have to train a little to get them ready to fight. Also keep in mind that she has a Kingdra with is Water/Dragon and can cause some serious match problems.
