The reference photo is really distorted-looking and poorly lit (too much of her is in deep shadow, which makes it hard to work from), and doesn't really match the perspective of the rest of the picture (if we're looking down at the girl, we also should be looking down at the pedestal and the flowers.) If you're going to use that pose, you need to get everything else working better so the persepctive disparity between girl and other stuff isn't so jarring.
I'd strongly recommend you shoot another photo (or actually, a whole card full so you have a range to choose from.) If you can't find a traditional key/fill lighting setup, at least shoot outdoors in daylight so the edges of the forms are better-defined. I'd recommend you shoot a more head-on angle if you're going to be inventing everything else in the picture; if you're committed to that overhead angle, you should include the flowers and furniture in the reference shot so they define the space more clearly.