"I'm someone who has something to say about this assault. It happened to me," she told TV3 at the time. In outing herself, she put a face to sexual violence in this country.
And last month, Ms Billingsley scored a victory for victims when her attacker, Muhammed Rizalman bin Ismail, pleaded guilty to indecent assault.
Her case served as a reminder of the gaps in New Zealand's justice system, where rates of sexual violence reporting are improving but are still relatively low, and prosecutions are rare.
Against her explicit wishes, her attacker was allowed to leave the country with diplomatic immunity. It took 18 months to bring him to trial, delaying justice and closure.
The problems, she said, went right to the top, where senior Government ministers appeared to dismiss her.
Her case also highlighted what she described as "rape culture" in New Zealand - the normalisation and trivialisation of sexual violence, often in subtle or unconscious ways.
She correctly predicted that she would become vulnerable after speaking out. She was attacked online, most notably in a popular political blog which questioned her account and her motives.
Like anti-rape campaigner Louise Nicholas before her, she gave weight to these issues by speaking out publicly.
Partly as a result of campaigns like hers, reform has begun in this area. Plans for specialist sexual assault court trials are under way and an inquiry recommends an overhaul of rape crisis services.
As she said in her only interview, "I just really think that we as a country, and especially the Government, need to start not just reacting to sexual assault but working to prevent it."
