For yourself and your girls, look at which place is most conducive to healing, personal recovery and building a strong support network around you. It's great news that you've found a good support group. Hopefully you'll be able to work in some Alanon or Celebrate Recovery meetings. I found that whatever meeting I can make it to helps to ease my anxiety when it builds. Working on meditation.
Is their dad able to have a solid positive relationship with them?
Did he follow through with rehab or does he have a counselor or sponsor to help him if he has relapsed? Do you think moving back would help him?