I don't know if this is at all what you were hopeing for but I gave my hand at PP on this one. I'm not a lighting expert so I often have to try to "fix" my mistakes.
This is what I did. I opened the photo with Camera Raw & adjusted in levels the highlights by -10, darks +15 & shadows +20 then opened to PS.
In PS I worked in layers adding a 50% grey layer & using a soft brush set at 9% opacity 100%flow painted with black over the blown out area & with white over the darker areas to lighten them.
I then flattened & added a warming filter @ 25% opacity, then copied the layer & added a gaussian blur at about 20% & 20% opacity on the layer. I removed the blur from the eyes & mouth with the eraser & changed the layer type to soft light to try to add some of the contrast back into her hair.
I hope this helps some, next time maybe try hanging a white sheet between the model & the window to help avoid the blown area, that or move the subject further away from the light source. I love natural lighting, but it definately has it's own difficulties.
Great shot too BTW, beautiful model & I think your assistant did fabulously!