If you are a Civil Servant then your normal retirement lmp sum will be circa 150% of Final Salary - so €75,000. However under Revenue rules you can get up to 150% of total earnings (averaged over 3years), so perhaps 150% of €70,000 = €105,000.
So I estimate that you could take a lump sum of €30,000 from your AVC fund. All €105,000 should be tax-free. The balance of your AVC fund could buy an additional Annuity or be invested into an Approved Retirement Fund.