You can try using leave-in spray conditioner on her coat and use a soft brush to get the extra dust off and distribute the spray. Any of the mane/tail/coat stuff works great. I love using that on m boy, he looks so shiny and clean!
There are also supplements and shampoos that work to improve mane/coat/feet that might help make her coat more lustrous. Unfortunately I don't know a specific one just for that off hand but I'm sure someone else will!