When Kara made her last roll, she said DC: 14.  What I am not sure of is whether the DC is still 14 if you are trying a head shot, or even if called shots are allowed.  I would imagine, based on what I do know of her combat system, that they are not.  If you roll several levels above the DC 14, you may be able to narrate it as a head shot, but I think that's about the only way.