I went through this last year and had no joy.
IMHO the leading sports shops in Dublin are more about fashion than function. I used to post queries on the rec.running newsgroup (via Google) and learned about the sorts of questions I should ask, or be asked, when purchasing proper running shoes. This newsgroup, predominantly US subscribed, assumed a level of expertise on the part of sports footwear stockists that, IMHO, does not exist in Dublin.
For example, when running are your feet subject to pronation or supination ? Also your weight and stride pattern should influence the footwear recommended to you.
All of this is of no use to where you are now. I ended my running ambitions in a half-marathon last year on old shoes and suffered for it for weeks afterwards.
I would suggest contacting an athletics club or getting a specialist magazine and see what stores advertise there. That may be one way of getting proper advice, instead of what's available in the main stores here.