St Luke's in Drumcondra has been purchased by Bertie Ahern's former secretary.
Grainne Carruth and her accountant husband, Eamonn O'Connell, plan to use Bertie's former constituency base as their family home.
Ms Carruth, whose evidence in the Mahon Tribunal brought about the downfall of Mr Ahern, previously worked at St Luke's for over half a decade.
Ms Carruth and her husband fought off other bidders to secure the property for €774,000.
The sale price is almost €180,000 more than Fianna Fail had sought when the property was put on the market last March.
It is understood Ms Carruth has always had an attachment to the building on Lower Drumcondra Road, where she worked before transferring to Government Buildings in the mid-1990s.
The couple are planning to convert the 1,900 sq ft property into a home for themselves and their three children, aged between 12 and 15.
Currently, St Luke's is made up of meeting rooms and an office, with living quarters upstairs.
The two-storey, red-brick building served as the nerve centre for Mr Ahern's constituency organisation during his time as taoiseach between 1997 and 2008.
St Luke's was bought by a trust comprising friends of Mr Ahern for £56,000 in 1988. The trust signed over ownership of the building to Fianna Fail in 2012.
Ms Carruth's evidence at the tribunal in March 2008, was a pivotal moment in the downfall of Mr Ahern - he stepped down as taoiseach two months later. She had initially insisted she did not remember making lodgements for Mr Ahern.
However, under cross-examination, she admitted that on the balance of probability, she had lodged Stg£15,500 to Mr Ahern's building society accounts and those of his daughters in 1994.