Walsh - Heffernan

My ancestors emigrated from Kilbehenny, Ireland to New York around 1850. I would like to find the exact date they left Ireland and determine if there are current descendants of the Walsh (currently Welch) or Heffernan Patrick Welch 16 Jul 1790 • Ireland Wife Margaret Heffernan (1795) Children Daughter Bridget Toole(1823–) abt 1823 • Kilbehenny, Limerick, Ireland Birth of Son Michael Walsh(1825–1906) 11 Sep 1825 • Kilbehenny, Limerick, Ireland Birth of Son Patrick Welch(1828–) 13 Apr 1828 • Kilbehenny, Limerick, Ireland Birth of Daughter Mary Walsh(1832–) 30 MAy 1832 • Ireland Birth of Daughter Catherine Walsh(1834–) 1834 • Kilbehenny, Limerick, Ireland Birth of Son John P Welch(1838–1918) abt 1838 • Kilbehenny, Limerick, Ireland Birth of Son Thomas Welch(1839–) 03 Feb 1839 • Ireland Birth of Son James Welch(1843–) 10 Jul 1843 • Ireland