William IRWIN and Eliza COWAN - my four great grandparents

I am searching for the following regarding William IRWIN, born about 1803 and his wife Eliza COWAN, born about 1808: Their birthplaces in County Armagh The date and place of their marriage in Armagh Also the birth date and birthplaces of their children: Mary, born about 1830; Margaret, born about 1831 and Thomas, born about 1833. Margaret is my great great great grandmother. This family moved to Canada about 1836 where they settled and had more children. Thanks, Linda