Gillen/McGary

I am looking for ancestors in Ireland of Michael Gillen, born Sligo 1801. He married Mary Ann McGary born 1802 in Sligo. She had 2 brothers, Michael and John, who emigrated with them to Ontario Canada in 1848.  Mary Ann and Michael had 5 children born in Sligo: William 1820, John 1830, Mary 1834, Michael 1837 and Lavina 1843. I am hoping to find some through DNA eventually, but am trying the good old way also.  Mary Gillen was my great gran and married Patrick McDonough in Canada in 1851. I know nothing of his life in Ireland or where he was from, wish I did.  He died before the turn of the century and my gran died when I was small. But many have the McDonough blue eyes, they are mesmerizing.