Sometimes just changing your dog’s food can make a big improvement. Here’s a link for top grade dog food. www.dogaware.com
You don’t say how old your dog is. If she’s an adult it’s possible she may have a thyroid problem, which at times can cause skin problems among other things. A flea(s) can also be a problem to the skin, especially if she’s allergic to them. To be certain as to what you are dealing with I would suggest an exam by your vet. Hopefully the dry skin can be helped by a simple change in diet and adding oil to the food.
I feed Innova or Wellness brands dog food. I also add Grizzly Salmon oil on their food. Some people use fish oil capsules and are very happy with them.
Here is a couple of links for shampoo and a spray on conditioner. I have used both with good results. Oatmeal based shampoos are also great for the skin.