Before entering state politics, Buchanan worked as a manager for Centrelink and served as a councilor for the now abolished Shire of Hastings. In 1994 she joined the Labor Party, and in the leadup to the 2002 state election gained preselection for the new seat of Hastings. Although the seat had a notional Liberal majority of around 8%, Buchanan narrowly defeated Liberal candidate Neale Burgess on the back of the Labor "Brackslide".
At the 2006 election Buchanan was defeated by Neale Burgess.
Buchanan was supported by EMILY"s List Australia in 2002.