At the party, witnesses saw the girl "wobbly on her feet and struggling to talk".
While in that intoxicated state, she was seen dancing outside, hugging and kissing Rolleston and Roche, the court heard.
One of them asked the victim's boyfriend if they could engage in sex with the girl, offering him $20.
The victim's boyfriend declined.
Roche invited the boyfriend to a fight, the court heard.
Judge Alistair Garland said it was clear he was so intimidated, he decided to leave.
Before leaving, he asked someone to put the victim in her mother's bedroom so she could sleep.
"One of you said; let's go back to the party" Judge Garland told the pair during sentencing.
"The two of you then took hold of her, lifted her out of bed, and carried her out the door."
A male friend described her as so intoxicated she would not have been able to walk on her own.
Roche and Rolleston took the victim into another bedroom and took turns having sex with her, which lasted around 15 minutes.
Afterwards, the pair joined friends in the kitchen.
Judge Garland says the two were "obviously very pleased", laughing and bantering with friends as they left the house.
Meanwhile, the girl was left to fend for herself.
She was seen stumbling into the hallway, naked from the waist down.
The victim awoke the next morning with no recollection of what happened, relying on friends to piece the night together.
During their two-week trial last month, both Rolleston and Roche maintained their innocence.
They said the girl gave consent, and insisted they had repeatedly asked her whether it was okay.
Despite two witnesses making statements to support this, Judge Garland said he was satisfied the jury found they weren't telling the truth.
The jury found the pair guilty of rape and sexual violation by unlawful sexual connection.
Roche and Rolleston were 18 and 19-years-old at the time of the incident.
The victim impact statement of the now 16-year-old was read in court today by Crown prosecutor Deirdre Elsmore.
"People used to describe me as happy and bubbly. I am no longer this person" it read.
"I did not deserve this."
During sentencing, Judge Garland noted the pair's lack of remorse and "arrogance".
"You appear to have little understanding of the enormity of your crimes and the impact on your victim," he said.
Roche and Rolleston's supporters packed the public gallery - and were told to remove customised T-shirts, which were calling for #justiceforbrookeandbrandon.
