New Mexico Custody Review?

My husbands ex currently has full legal and physical custody of their four children and resides in New Mexico. She was only awarded this because we live in Pennsylvania and my husband wasn't able to see them for 8 years both because of financial reasons as well as her not letting him. We had the children over Christmas for the first time ever and it went pretty well. The children are being neglected, point blank. We were told by a lawyer that we could ask for a review of the custody case after one year. It's been a year and we would like to go back to court but have no clue how. The children are never together and their basic needs are not being met but we really have no way to prove anything. She is always working her two full time jobs and still complains that she never has any money even though the child support my husband pays her covers her rent and utilities. We are just at a loss because we cannot afford a lawyer and the children need away from their destitute town. Any help or suggestions will be GREATLY appreciated! Thanks!