I was born 2/20/1976 Massachsetts-looking for birthfamily

I am looking for my birthmother and 2 half sisters 6 and 10 years older than I. From what I have found out I was born in Newburyport Mass. at the Anna Jaques Hospital to a woman in her mid-late 30's. She was unmarried, lived w/ her mother, worked in a factory, 2 brothers? one was a truck driver, my grandfather (her father) died at 73 and was a farmer i believe. My adoptive mother thinks my temp. name may have been Kelly. My birthmother was approx. 5'8 dark brown hair, brown eyes. My birthfather never knew about me - he was over 6ft, light hair and eyes. I was adopted in New Hampshire via Child & Family Services in Manchester, at 10 days old. The case worker was Bernice Johnson.