Cost you? Hmm.. how about a ham sandwich?
Seriously... you can switch to any spell you wish to cast, but be aware she has only the one wolf in front of her which is now behind the party. The others are still beyond the defensive line formed by the guys. A color spray spell there could be a problem. Now if they get past that line then a color spray could help out if she warned the group first.
If you have further questions, let me know.