you should give autotrader a try as they cover cars and extras in both the north and south of ireland the aldo break it down into provinces as well they also have an online site but i find the magazine a lot handier and as they say "it's available in all good newsagents" lol should get a job with them. Best of luck anyhow. p.s. give buy and sell a shot u might get good second hand ones there
have a look at http://www.eiretyres.com You can input the size of tyre you are looking at and get various prices ranging from the priemum to the budget brands. Also have fitters all over the counry. I know a few lads who used them for high performance tyres and they reckon they saved quite a few quid