for this shot, i'd go for a tighter crop on the face. i just did a quick crop in paint (i'm at work) to see how'd it look. i cropped a little off the top of her head, brought in the left side until it reached the necklace, brought in the bottom until it was a little above the cross just below her collarbone, and brought in the right just a little bit.
i feel this makes for a more powerful photo.
one other thing i noticed (not too sure if it'll improve the photo or not) but it seems the highlights on her cheek and the shadows on her hair are blown. if this was done on purpose, try the photo w/o blowing the highlights and shadows and see how it looks compared to the current one.