Droch, a chara,
Tá cúpla smaoineamh duit:
I've heard good things about Gaeltalk (
http://www.gaeltalk.net/index1.html)
and their e-tutoring program.
I like Now You're Talking/Irish on Your Own, the book/tape set.
Maybe a blend of attending Daltaí na Gaeilge events (and those of other groups) plus some at-home studying would work for you. And an occasional immersion course in Ireland, at Áras Uí Chadhain or Oideas Gael.
Ádh mór,
Paul