Contractors prices have come down a lot in Clare. We have just started our build and for house it is costing about €67 a sft to builder finish ( floors and kitchen not included, but sanitary ware is), but that doesn't include garage etc. It does include slate, solar panels, back boiler on stove and oil heating and a fairly high spec of insulation. Our builder said that in the boom he would have been quoting 90-100 for the same spec. He is very busy at the moment - just having started at least 2 other house builds in the last few months and has a few extensions to do as well. Good builders are still busy! This contractor was no1 on both our architects and engineers list, but like all still needs to be watched.
As other posters mentioned - it will cost more depending on what is needed in the renovation - but for the new portion of your build you should be looking at 65-70 per sf.
We also got a quote from builders outside of Clare - one from Galway and a big firm for the midlands. We wanted the best price with the most included. The more you know about your build spec beforehand, the closer to the end price you will be. Some of the quotes we got back didn't include some of our spec details, so were worthless and some builders wouldn't sit down to discuss what was or wasn't included. We like the contractor we did go with as he gave us the bill of quantities, so we knew exactly what he was including in the quote and as a result we could see areas where we could save money and areas which will be subject to change due to a p.c. sum being supplied. Our contractor said these were all external companies and if we found we could get a better deal, he was happy to go with those - he wasn't adding any loading onto the pc sums.
There will always be unknowns with a renovation - just make sure you have plenty put aside for unknowns.
best of luck with it!