Is she the one on the left? I have to admit, something about her doesn't look full-yorkie to me either (and I mean NO offense with that....people told me the same thing about Kiki too....and I AGREED with them!
)
But I think a trip to the groomers to shape the hair around her face a little would really help!
You can't see the rest of her body well in the pic, but again, Kiki had VERY (impossibly!) thick hair, and I finally shaved her into sort of a schnauzer cut (left legs and head long), and I have to say, she looked MUCH more "yorkie-ish" after that! But yes, I have read about people using thinning shears to cut out the bulk, and leave the length.
Good luck!