After a brief trip back to Ireland she returned to New Zealand, again for what was supposed to be a short trip, only this time around the North Island.
"And what do you know, I'm still here."
"I just fell in love with the place. Like Ireland, it's very green and its people are friendly."
Ms Foster said she was thrilled to become a New Zealand citizen, even if it meant she would get a bit of a hard time for supporting the Irish rugby team.
"I still want to see the Irish beat the All Blacks. It has to happen at least once in my lifetime," she said.
Now living in Rotorua, Ms Foster has lived in towns across the country including Nelson and Papamoa.
She said she now calls Rotorua home.
"I really think that home is where the heart is and for me, it's here."
Yesterday's ceremony was conducted by Mayor Steve Chadwick and cultural ambassador Trevor Maxwell.
Students from Sunset Primary School performed songs and a haka during the ceremony.
Others who got their citizenship yesterday hailed from the Philippines, England, Sri Lanka, South Africa, the United States, India, Zimbabwe, China, Thailand and Malaysia.