Trying to find link to heritage

My spouse and I are traveling to Ireland this coming summer (June 2013), a trip we've waited decades for and am interested in learning more about my specific past. My father's mother's maiden name was Carey and she actually left Ireland to come to America during the late 19th century. Unfortunately, my father was an only child and this is all the information I have. Her name was Mary Carey (maiden) and married a man (my grandfather) named Robert Beyer in New York City, N.Y. My father was an only child and both my grandparents had died before I as born. It is all I have. Not sure this is helpful at all but any assistance would be greatly appreciated. Thank you, John Beyer