Also, don't forget that the first €1,270 of taxable gains in a tax year are exempt from CGT.
In the most simple cases, an asset owned as a PPR for 8 years and then sold after 2 years of non-PPR status with a gain of €20,000, would be classed as exempt from CGT for the first 8 years and the final 1 year - meaning €2,000 (10%) would be liable for CGT. In this case, CGT would be due on €730 after using your annual allowance giving a total tax of €733 * 33% = €241.89.
However, in your case, I believe Indexation may come into play - which would reduce your liability further. Others will be able to confirm or deny this as I am by no means an expert.