Thank you for trusting JustAnswer with your important question.
There is a trauma therapist in your area who may be a good fit, and may know of more resources in your area: http://www.marikapollak.com/index.htm
How much therapy is required for MPD/DID really depends on too many factors to have a set answer. Some people need weekly therapy, some need more than once a week, and others are able to go to less frequent therapy once they are more stable and out of the crisis phase.
Many can not afford intense therapy, and may need to use self-help groups, books/workbooks, online support groups, and other resources to help their recovery process.
Two good places for finding information and therapist listings are:
Some workbooks you can order include:
Life After Trauma, Second Edition: A Workbook for Healing by Dena Rosenbloom PhD and Mary Beth Williams PhD
Healing the Trauma of Abuse: A Woman's Workbook by Mary Ellen Copeland and Maxine Harris
Mind-body Workbook for PTSD: A 10 Week Program for Healing After Trauma by Stanley Block and Carolyn B. Block
Books about DID that may be helpful are:
The Dissociative Identity Disorder Sourcebook by Deborah Bray Haddock
Amongst Ourselves: A Self-Help Guide to Living With Dissociative Identity Disorder by Tracy, Ph.D. Alderman and Karen Marshal
It is important to find a therapist who understands trauma and dissociation, and who has worked with MPD/DID before. Many "general" therapists may not have the skills to help get you out of crisis mode and on the road to recovery.
Your insurance may not cover treatment for MPD/DID, but it probably does cover treatment for Post Traumatic Stress Disorder. Therapists sometimes have to use the PTSD diagnosis instead of the DID diagnosis in order to get adequate treatment approved. This is not uncommon. They key is to realize that DID is related to PTSD, and therapy to reduce the PTSD symptoms will ultimately help reduce the dissociative symptoms.
Oh, I forgot to address your last question!
Yes, people with DID typically hear internal voices. They usually understand that these voices are part of them, and not coming from external sources (for example, they weren't implanted by the government).
Not all alters are equally aware of each other, so some may actually see and experience other alters inside as developed "selves" while others may only hear the voices and not really be able to communicate with the other voices.
This website might help you better understand more about DID: http://2multiples.com/twcrew/47_page.html
Many people with DID are inaccurately diagnosed as psychotic, Borderline Personality Disorder, or Malingering, or even Rapid Cycling Bipolar when their doctors do not fully understand DID. Research shows that it can take an average of 7 years for people to be properly diagnosed!
What you describe could be DID, and trauma/PTSD treatment is something you should pursue since other treatments have failed.