I agree with guilloche. Call your insurance provider and ask for a list of therapists in your area that are taking new patients. Sometimes you can access that list online. If you do call them, I would definitely mention that the providers you're calling are telling you that they aren't accepting any more patients with your insurance.

I don't have private insurance anymore, but when I did, I also had a good PPO plan. It was excellent for medical care and had good psychiatric inpatient coverage, but its payment for psychiatric outpatient care was awful.

Another option sometimes is to go through a mental health care "agency". They're not as nice to go to as a private provider. They usually don't let you choose your own therapist. I went to two different ones at times when I had the PPO, though, and got a good therapist.