You send Revenue evidence of the contribution (e.g. receipt and/or updated RAC or PRSA1 certificate) with a note asking for tax relief. Once you get tax relief you can claim PRSI relief as per the thread in the key posts section. You should aim to get your payment AND claim in before October 31st as some people were claiming that Revenue were rejecting claims after that date even though I'm sure that I did this in the past.