Catherine Walsh or Welsh born 1824 in Levallinree, Turlough, Mayo, Ireland

I am the 2x great-granddaughter of Catherine Walsh/Welsh Roche who was born in 1824 in Levallinree, Turlough, Mayo, Ireland and died in Whitewater Township, Dubuque Co., Iowa on 16 Nov 1859. She marriedThomas Roche (born in vicinity of Castlebar) in about 1840. They had 4 children born in Ireland (including my great-grandfather Henry Roche) and 3 born in Iowa after the emigrated. Catherine's gravestone in Iowa indicates she was a native of Levallinree, Turlough, Mayo, Ireland. I have not been able to find any information on her parents or her birth. Any suggestions? Mary Dahlstrom-Salic