I was also an Angel Guardian Home child who knew who my birht mother was, but not my birth father. I was never adopted because my birth mother didn't give them permission so I was in their foster care system since my birth. Although I was fortunate to have found out who my birth mother was, I never knew who my birth father was although most people told me he was abusive man and an alcoholic.
I never really dwelled on the fact that I didn't grow up with my birth parents, but I did make contact with my birth mother on several occassions before she died. I have to admit the entire experience wasn't as an emotional as I thought it would be, and I treated it like finding a long lost distant relative. I didn't give much thought about finding out about my birth father until I was much older than you. I just decided one day that I would try and see if I could get any formation from AGH. What I did find out was that AGH had kept all of their adoption and foster care records, despite a New York state court ruling sometime in the 80's or 90's that foster care and adoption agencies could destroy their records to protect the names of the birth parent(s). It had something to do with the fact that AGH was a Catholic organization and was exempt from that ruling. Anyway, In early 2002, I was very fortunate that I was able to make contact with someone there who was very sympathetic to my cause. They not only sent me my original file, but also the files of my brother and sister. I don't think you could do that today without the help of legal aid or a lawyer, but I do think your files are still there.
For what it's worth, in my case I found that although the information in my file was very interesting (I found out that my birth father, who had passed away many years earlir, was not the same person whose name I carried) I really enjoyed reading the monthly social worker reports that it contained. It was like reading a novel about my entire life as I was growing up until I reached 18. I wasn't overwhelmed with any emotional feelings, just fond memories of things written in those reports (many which were not very complimentary) If anything it reminded me of the things I missed about not growing up with parents, but today it is so commonplace I feel very fortunate how my life turned out. Despite enduring the stigma of being a foster child who was constantly being placed with different families over the years, I became a very successful businessman and really feel the experience was a major factor in motivating me in the right direction. I wish you the best of luck in your search for your birth mother and if anything, I'm living proof that if you don't give up something may come along unexpectidly, that opens the door to the information you seek.