Mr Warren visits Valentina at the cemetery every day. Ms Perera goes to the cemetery at least every weekend and the couple go together on special occasions.
"We include her in everything. We put a stocking up for her at Christmas and took a present to the cemetery.
"We see Augustina as a blessing from Valentina. She's her guardian angel.
"We talk to Augustina about her sister and will talk to her more and more as she gets older so she knows how special her sister was."
Speaking about the specific details of Valentina's death is too painful for the couple.
"No one is to blame. It was a heart-breaking, tragic accident," Ms Perera said. "We don't want to dwell on it."
Ms Perera still wanted to be a mother after Valentina's death but worried she wouldn't get pregnant again.
"Pregnancy is hard enough without all the stress and grief I've gone through. You don't know when it's going to hit you.
"People asking if it was my first child; innocent comments by nurses and people who didn't know, were really hard. I don't think we'll have any more children."
It was also difficult not to compare her two daughters.
"Augustina looks so much like her sister. I look at her and remember how Valentina was when she was only a couple of weeks old.
"Valentina was such a vibrant girl. She would have loved to have a little sister.
"She loved other little kids, and they loved her. The kids she used to play with still ... miss her."
Ms Perera hoped other parents who had lost children would find happiness again.
"I could have just buried myself under the covers but I know Valentina would have wanted us to keep going. She'll never be forgotten; we miss her every day but we have a kind of happiness again.
"My advice to other parents is, don't hide away. You have to take each day as it comes."
Five children are killed on average each year on New Zealand driveways.
Starship receives about one child a fortnight with driveway injuries. Most injured children are aged 2. Almost 70 per cent of accidents occur when a car is reversing.
SafeKids Aotearoa has repeatedly called for drivers to be vigilant for children around driveways.
In October last year, the organisation launched a new awareness initiative, Check for Me Before You Turn the Key, in which it distributed keyrings designed for parents to put a photo of their child in so as to create an "emotional link" to driving.
Child safety tips
• Identify risks like long driveways, those providing pedestrian access to a house, and those near parking
• Check for children before driving off
• Supervise children near vehicles
• Separate play areas from driveways.
