Normally your FTB status runs for 7 years from when you first took out your first mortgage (2005 - 2011). Because you sold your PPR in 2008 you only used 4 years of your FTB status.
If you ring the TRS helpline (1890 46 36 26) and explain to them that you are no longer a mortgage holder and would like to freeze your FTB status until you buy another property in the future. That way you will be able to avail of your last 3 years FTB status in the future (if you don't contact TRS regarding your position, your FTB status will automatically cease at the end of 2011)
Based on the changes announced in the last Budget, once you purchase a new home in, say, 2010, you will be entitled to 7 years TRS on that new mortgage.
2010 - 2012 as FTB status
2013 - 2016 as nonFTB status