What training classes have you done? I'd suggest a class where you can learn how to get her to focus on you in a controlled situation.
When my boy was younger and thrilled to bits to see another dog I found Leslie McDevitt's book, "Control Unleashed" to be a big help. She calls her techniques games. Premack principle is not new but her presentation is fresh. Even better would be to find a trainer who understands it.
ETA: If your girl is truly aggressive you need professional help. If you are not sure if she is or you can't tell you need professional help.