Claire has set up a Givealittle fundraising page to help raise enough funds to enable her and her adoptive mother to visit her birth family in Romania possibly sometime next year.
Claire, who understands she also has at least one other birth sibling, was one of the thousands of children hidden in orphanages across Romania during the communist rule of Nicolae Ceausescu.
In 1989, Ceausescu and his wife, Elena, were tried and executed for genocide and sabotage.
Claire said once her birth sister made contact she was initially sceptical but once they exchanged more key information only she and her adoptive mother knew she became very excited.
"It was then that it hit me I might also be able to meet my birth mother if she wants to see me. I would love to be able to tell her I'm happy, I'm healthy and I have an amazing family, and reassure her there are no bad feelings. I want to tell her I'm so grateful that she gave me up for a better start in life and, if it wasn't for her, I could ... possibly be even dead."
Claire said her adoptive parents, Sue and Neville, were "fantastic people" and she had an amazing family, including two siblings, Jodie and Benjamin, also adopted.
Mrs Thomasen said she couldn't have children of her own but was desperate to have a family, and after adopting her two oldest children in New Zealand started looking overseas for more.
She originally planned to search in Colombia but after reading a news article about the plight of the thousands of Romanian children who had been hidden from the world it meant a change of plans.
Mrs Thomasen said the orphanage where she found Claire was "horrible and cruel".
"Room after room was full of children. Most of them showed no expression, and there was no noise and little attention being paid to them and little in the way of nourishment. I was taken into a room where Claire was. She was the only one who showed any reaction to my visit and she grabbed my hand. I thought this is the one and my heart melted," she said. "When I first saw Claire she had little hair, no teeth, and had never eaten solids. She couldn't talk, walk or even crawl because she had never been out of her cot. Despite her being almost 2, she looked like a 6-month-old."
Mrs Thomasen said adopting Claire was a highly complex and lengthy process, meaning "masses of paperwork" and lots of bureaucracy to overcome.
"I intended to also adopt a little boy but tracking down his birth parents proved too hard."
Claire was originally refused entry to New Zealand and it was only after the family's lawyer threatened legal action and a Paul Holmes documentary about their legal fight that the red tape was finally cut.
The family and Claire first lived in Waihi before moving to Tauranga when she was 14.
Mrs Thomasen said: "I think it's wonderful for Claire to find her birth family and to want to reconnect with them. I feel quite secure about that because I know I'm still her mother ..."
To help Claire get back home visit www.givealittle.co.nz/cause/Getclairehome