The Family of Mary-Ellen Deighan-Rosekrans

I'm looking for Deighan family members who originally came from Ireland imigrating to Rhode Island. My grandfather was James Francis Deighan, grandmother Helen McCann. Their children: Mary Margaret, Joseph Thomas, & John Edward. My mother is Mary, she married Melvin Francis Grenier also from R.I. They were married in 1950 I believe. He adopted me on Nov. 6,1958, and my name on the adoption certificate is Mary-Ellen Regan. I'm not sure yet what name is on my birth cert. I'm also trying to find my birth father, my mother is unable to give me any information. If anyone is able to help me, it would be greatly appreciated.