Are you willing to get some assistance from the Department of Juvenile Justice or are you inquiring about treatment options for her? She can still refuse treatment and continue to act this way especially when in a year society will consider her an "adult".
The Juvenile Justice Dep can provide some feedback on how to handle an unruly teen.
If you're seeking treatment options, it would be best that besides individual counseling (if she's willing to engage in that) there is family counseling as well. Her behavior is affecting the rest of the family and even your own reactions to her can be affecting her as well. If she is willing to get therapy, you may explore what options are available from your insurance plan. It would most likely take place at the outpatient level. If you are connected with a church, you may encourage her to talk to the youth minister as well. But, this whole situation has to be approached from a family perspective and not single her out as the "bad apple" Otherwise she will resist and may resent you.
Do you know what she's willing to do?
She cannot do a whole lot without your support especially if she financially dependent on you. Even if she is to get a job, does she think that they money she will be getting will be enough for her to live sufficiently and independently? Let her do some research as far as what each job pays, what experience and education she has to have, how much does it cost to maintain a living from having a car, apartment and all living expenses covered.
If only has a year or so left to finish school, it may be best that she finishes what she had started. Point out to her that otherwise it is wasting resources and effort.
You may suggest to her to speak to a career counselor at her current school. They can help her with objective feedback if she does not believe what you're telling her. You could also present it to her that she could speak to a counselor elsewhere because it does not seem that her plan is a workable one. That she has to look at whether the information is coming from you or someone else.
If she relies on you for her car, cell phone, money, etc. you can limit her to only the most essential- food at home, shelter, etc. All other "extras" if you're paying for them ought to be taken away and earned by her even if you use them as a reward for going to and finishing her school..
The Department of Juvenile Justice can help because from what you've shared, she's an unruly teen/still a minor. If she is not respecting the family rules, she may have to be told by others what to do. There are consequences for unruly teens. Phone the dept of juvenile justice at least to see what assistance they may offer.
You may want to talk to the parents of her friends versus to friends themselves. She is not being forced or held against her will at these friend's home- its her choice.