She slammed into the vehicle side-on, the impact crushing her leg between the 4WD and her bike.
"All I remember is hitting the car and someone took the motorbike off me and put it alongside the road," Ms Rosa told the Herald from her Auckland City Hospital bed last night.
When she came to, she was still wearing her gloves and helmet and was surrounded by motorists who had stopped to help.
"One was cuddling me, one was holding my hand and another person was picking up my stuff from the road."
But at some point, she said, a thief picked up her bike and rode off while others were tending to her.
She only realised this when a woman, on the phone to the police, asked her for the registration number.
"I said sorry, it's on the bike, and she said, 'the bike's not here'. I said, what do you mean it's not here?
"Then she said someone had taken the bike. It's been stolen."
A nurse at the scene attempted to move her leg and found it was broken.
Adrian Ironside, who lives across the road from the intersection, said: "I saw her lying there on the road, then I saw someone moving it to the corner, and the next thing was I looked up and the bike had gone.
"It's just bloody awful that someone would do that. I don't know what this city is coming to."
For Ms Rosa, who is from Rio de Janiero, the crime was something she would have expected more in her home country. "I wasn't expecting this to happen in New Zealand because it's the safest place I've been in my life."
Police were searching for the bike, worth up to $3000, but by last night had not found it.
Ms Rosa expected she would never see it again, but said her thoughts were more with those at the scene who had helped her - ambulance staff, and the nurses, physiotherapist and surgeon at the hospital.
She underwent surgery to restructure her tibia yesterday.
"But I think it could have been much worse. I'm alive."
Ms Rosa hoped the incident might be a lesson for others. "We'd hope that people extend a hand to help, rather than try to take advantage of a situation."
