Potential advisor does not seem willing to accept me into group. How do I approach others in the same field?
That is a tough situation. Any advice should depend on the specifics of your school. But I would advise to ask another professor to join their group, and when asked about going to the original professor simply say very briefly that she was not very interested in your idea (not in you personally, your idea) and so you wish to try with other professors. Don't give too much details.