:iagree: with several other posters that you should read up on RAD and find support groups.
I have two girls that have been with our family for 1 year and 3 months. I never truly realized what we were getting into at the time. I just thought that if we showed them love that would be all they needed. The first few months with the youngest was wonderful. The older girl caused many problems at home and school. Now, the roles are changing and the younger one is a COMPLETE nightmare! I can't believe some of the strong-willed, devious behaviors that can come from a 3 yr old.
Both are beautiful, intelligent girls and it breaks my heart to think what they've been through. However, I will say there have been many times I just wanted to send them back into the system. Fortunately, I had family members and now a support group to help me through it. (BTW - these girls are my cousin's daughters but I had never met them until we found out about the situation and decided to try for placement).
We also have two biological boys. Even though we prepared the boys for the addition, it has been very tough on them. They were always so good with playing together, sharing, etc. The girls were not. The oldest girl is finally playing well with our boys and is becoming less selfish.
Prayer is going to be vital in this situation - for the boy, you, and your family as a whole. May God bless you in this journey.