Looking for Fitzpatrick Ancestors

I am looking for the parents of my g-g-g-grandfather, Philip Augustus Fitzpatrick, born in County Cavan around 1828 and died in New York City in 1874, where his obit listed him as a native of Drumlane Parish.  He immigrated to New York around 1848.  He was a builder and developer and became quite successful before dying at age 44 of tuberculosis.  He married Bridget Daly (1833 - 1910) about 1854.  She was born in County Cavan and was the daughter of James and Bridget Christy Daly (the whole family immigrated to New York City before 1850).  Confirmed siblings of Philip Fitzpatrick are:

1.   Bridget (1821-1860) a resident of New York City, who was listed in her obit as a native of Belturbet.  She was married before 1850 to Robert McGuire (1814-1854 -- born in Ireland, died in New York City). 

2.  Hugh (1837 - 1862).  He did not marry.

Possible siblings or close family members include:

1.  Catherine "Kate" (1835 - 1880).  She is listed as born in Belturbet, died in New York City.  Married to Francis "Frank" Blessing (1812-1903), a native of Drumlane Parish.

2.  Margaret (1830 - died after 1903).  She never married and lived with Francis Blessing and Kate Fitzpatrick Blessing.