No more recent updates on the case itself, but a few more details on the incident and people involved can be found in these links:

An Irish Indymedia / Saormheáin Eiréann article from June:
Teacher arrested for speaking Irish
(Tacaíonn na Gaeil Óga Le Máire Nic an Bhaird - Cearta Teanga, Cearta Daonna) (Page down for the English translation.)

A brief report from the Irish Times:
http://www.gaelport.com/index.php?page=clippings&id=1250&viewby=date

And from the Irish Independent:
http://www.gaelport.com/index.php?page=clippings&id=1246&viewby=date

And from the Scottish Socialist Voice:
http://www.scottishsocialistvoice.net/back%20issues%2006/issue%20276.htm
(Page down to page 11: "‘Leprechaun language’ taunt dents new image for Six Counties’ cops").

I'm sure some of these were covered in the Celic League PDF, but as PDFs crash some computers...