There's a more actuate translation of a longer six verse version in: "A Hidden Ulster; Songs, Traditions and people of Oriel", by Dr. Pádraigin Ní Uallachain. It also includes the original text and prints from manuscripts.
For example the first verse translates:
'The Green Hill of Cian Son of Cáinte
Flower of maidens of fairest face,
Famed for human splendor,
Head of curls, beloved of poets,
Enhances warm and welcome;
Face as the sun each bright new dawn,
Banishes grief with laughter;
It is my sad woe, love, that we're not alone,
In that fort of Cian, son of Cáinte.'
hope that is of help