She is called a cinnamon pied pearl. Pied is a grey + lutino cross and then of course the pearl is with the spots on the wings and cinnamon means that her "grey" markings have sort of a light brown cinnamon color to it. She's considered a triple "mutation." Odd word for it, but that's what it's called.

This link kind of explains it and shows another example.

http://www.cockatiel.org/mutations/cinnprlpd.html