The 4-month-old had ventricular septal and atrial septal defects, meaning her heart is weaker than a healthy child.
"This in turn has caused her to have fluid on her lungs, which makes it difficult for her to drink and breathing has become slightly more difficult," she says.
Karmady is a miracle, as she stopped growing at 32 weeks in utero and was born with Down syndrome.
Despite all prognoses, she lived.
"She is our little miracle heart baby, and against all odds and all the diagnosis we have had for her over the pregnancy, she fought through it all," her mother says.
It took five weeks after giving birth before Tawhara and her daughter could be reunited.
"We spent two weeks at Starship Hospital, then three at Waikato Hospital before we could go home together.
"I did not even get to spend the night with her in the same room all this time. It was hard, but every morning and night I was there to see her."
With the surgery soon and the post surgery treatment required, Tawhara has taken a short break from her busy career as a chef.
She has a stall at the Underground Market selling handmade soaps, candles and other bath products, and can take her daughter with her all day.
"It has been a really good timing that this place [Underground Market] popped up when it did. She has got her little bed here. That way she can just stay with me all day.
"My mum also can stay here while I have to go to the hospital. She is my life-saver."
Karmady also needs to have an MRI to check for any brain damage before her surgery.
"After the surgery, we will be looking into hearing aids as she is moderately to severely deaf in both ears, but we are just dealing with one battle at a time."