Belgard Cleaners, Abberley Centre, Tallaght 24 Dublin, Tel (01)4517396 are quite good. They are in the same complex as the Abberyley Hotel/DID/Smyths Toys.
There is an old fashioned shoe repair shop on the old main street in Tallaght Village and they might be able to do something with the belt for you. IMHO it is better to [broken link removed]yourself as it can come in quite handy and as far as I can recall they are not too dear. I bought one many moons ago in Arnotts but I don't think they stock them any longer. You should be able to get one in Trimmings who are now in Liffey St. beside the Woolen Mills. Not sure if
Hickeys would have them.
HTH.