Helen I was very sad to read your post and feel sure cyber/gamma knife is available here!
Try e mailing St Lukes
http://www.slh.ie/departments/radiotherapy.php
If not, I think the HSE will cover the cost to another facility in the UK but not too sure as haven't checked fully.
You're not the walking dead and can beat this as other's have, this regime just was'nt sucessful for you but there are other's ton choose from. I know the part of the country you're in and if you feel you're not getting the best care try switching to somewhere in Dublin. I attend Tallaght and have been very happy with my care there.
My best wishes to you and mail me if you want to chat ((((hugs))))