I will now give the verses from Ó Baoill, Ceolta Gael 2, even though they are similar to other versions given above. There is a cassette tape available with the book.

THUGAMAR FÉIN AN SAMHRADH LINN
Babóg na Bealtaine, maighdean an tsamhraidh,
Suas gach cnoc is síos gach gleann,
Cailíní maiseach go gealgáireach gléasta,
Thugamar féin an samhradh linn.

Samhradh, samhradh, bainne na ngamhna,
Thugamar féin an samhradh linn,
Samhradh buí na nóinín glégeal,
Thugamar féin an samhradh linn.
Thugamar linn é ón gcoill chraobhaigh,
Thugamar féin an samhradh linn,
Samhradh buí ó luí na gréine,
Thugamar féin an samhradh linn.

Samhradh, samhradh, bainne na ngamhna etc.

Tá an fhuiseog ag seinm is ag luascadh sna spéartha,
Athas do lá is bláth ar chrann,
Tá an chuach is an fhuiseog ag seinm le pléisiúr,
Thugamar féin an samhradh linn.

Samhradh, samhradh etc.

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According to http://www.opengroup.com/mubooks/185/1851826858.shtml , Pádraigín Ní Uallacháin's new book Amhráin Oirialla - Songs of a Hidden Ulster Published by Four Courts Press (ISBN: 1851826858) costs $126!
It's a 450 hardback book with illustrations and Audio CD (according to notes with the Dealg Óir album, there are 2 CDs containing 54 songs sung unaccompanied). An Dealg Óir, issued by Gael-Linn, contains a smaller selection of the songs from the book, sung with musical accompaniment.