Under the split year rule you should be entitled to a full years tax credits provided you will be tax resident in 2014. If you applied for tax credits in 2013 they were probably issued on a week one/month basis and you can get a full year tax credits by asking for a review of 2013.
You are liable to tax on the rental profit on your house regardless of where you were resident. You may be entitled to a proportionate part of your tax credits for the 3.5 years that you were away - formula is Irish income/worldwide income.