Looking for Kin of Robert Garnsey from New York State Oswego Fulton Watertown Area

I have obtained my birth certificate and found out my last name is Garnsey my mother was betty heath and never told me about Garnseys i am 54 yrs old and just found out about all this in the last year any help with this would be a blessing,some other info may help /mother betty j heath was born in michigan had 2 sisters violet(joyce)heath and jeanette heath and a brother name unknown 2 me fathers name was frank my grandmothers was vic i also think robert had like 10 brothers and sisters his mother may have been mable/ mabel not sure please help if you can andas far as my father i am only looking to find out who i am not looking for anything except the facts i am 99% sure he dosent know i exist as the story told to me is my mother went to mexico and got a divorce and remarried don isaacs and just started using that as my last name with out any paper work guess in the 50s that was ok lol not today for sure thanks to all that can respond have a great Christmas!!