The song in question was recorded by Gary O'Briain and Padraigin Ni Uallachain on their record A Stor A Stoirin - Songs for All Ages; online listings don't specify the label or date.  It has also appeared on a compilation CD of "Celtic" lullabies.  The original record has a booklet with Gaelic lyrics and English translations, so you could always try buying it.  A generic song title such as Lullaby and Lullaby isn't likely to be easily identifiable by anyone who doesn't have the record from which it came...