Flax seed oil, or fish oil should help with dry skin. It's probably a good idea to limit baths and only use shampoo when necessary as shampoo washes away the skins natural oils.
You might try adding some oils to her food. Salmon Oil, flax seed oil and even olive is good.
Sorry to come into the post a little late...if a dog can't handle salmon/fish oil, is flaxseed or olive oil a good alternative, or would they tend to cause the same tummy upsets?