I'm not with an agency, but I do work for a film production company and we often hire models and young actors for commercial shoots, television pilots, etc.
If you aren't having any luck finding a modeling agency, I would reach out directly to local production companies. This can just mean sending a comp card and/or head shots (make sure to send it to the attention of the production manager, casting director or producer, dependent on the size of the company), be sure to include a resume highlighting any acting experience, other talents, etc.
Depending on the shoot, whether its a union job, etc, many times we'll end up hiring models and actors directly, instead of going through a modeling agency to avoid a markup. This in turn will add credible experience to her resume, making her more attractive to modeling agency.
Good luck! She's gorgeous and has a real spark on camera, I would hire her!