I have two suggestions for you.
First, there is a wonderful article written by Colleen Bucker, aka the Search Guru written especially for adoptive moms. She is an adoptive mom who searched for and found her daughter's birth mom. Here's the link:
http://e-magazine.adoption.com/artic...ve-parents.php
There is also a booklet called: Courageous Blessing by Carol Demuth (another adoptive mom, I believe) that she might want to order.
Many adoptive parents are unaware that reunion can bring adopted children closer to their adoptive parents too - something your mother has already figured out. Just think that it is good to keep reminding your adoptive parents that your heart is big enough for two sets of parents.