Sadly, Kristie's body began rejecting the lungs at the start of this year and the mother-of-three died on March 21.
The sisters were well-known in the community for their 65 days of good deeds to raise money and awareness for the illness.
Kristie's children had carried on since her death and were spending a lot of time with Nikki to make sure they could all still share memories of the mother and sister they lost.
A month ago, Nikki got engaged, which she says was a big surprise.
She says she has started wedding planning and has constantly had Kristie on her mind.
"I will incorporate her into my wedding everywhere I can. I am going to have purple flowers in my bouquet and her young daughter Hayley will be one of my bridesmaids."
Purple was Kristie's favourite colour.
Nikki's cheering business had also moved from strength to strength, with her little girl Skylar and Kristie's daughter Hayley both top dancers in it.
In other good news, Nikki and Kristie's brother had a baby girl, which had brought joy to the whole family.
Nikki says she is feeling great health-wise and is having no trouble since her lung transplant.
She says it is always a worry that what happened to Kristie may happen to her.
Nikki is currently in the process of planning a 65 good deeds event in Kristie's memory for next year. It is something Nikki says she is looking forward to.
In the past six months, Nikki says the support from the community and everyone around her has been incredible and she is so thankful.
Meanwhile, the official launch date next month for a charity set up in Kristie's honour by Melanie Quin has been set.
The charity, called A Day of Magic, is designed to grant terminally ill patients the option to have an unforgettable experience or tick something big off their bucket list in their final days.
Before Kristie died, Quin organised an incredible day for her filled with a catamaran trip, a helicopter ride, and a dinner and performance by Tiki Taane, with all her family by her side.
The charity had teamed up with another charity called Donors Choice and Tauranga Crossing to organise an annual family fun run and walk at The Lakes.
She had also secured sponsorship from the owners of the Breakers restaurant chain, who offered to put donation boxes in all their restaurants across the country.
Breakers Restaurants chief executive Stefan Burt said they were proud to get behind a charity that would bring some light into the lives of Kiwi families who are doing it tough.