Ross told her he was there on behalf of the Mongrel Mob to collect rent money, and when her partner confronted Ross, he brandished the knife at him.
The woman's partner was a member of the Mangu Kaha chapter of the Black Power gang and was known to Ross.
He told the victims they needed to pay the Mongrel Mob rent for being in their area, and would not leave empty-handed. He fled with their wallet containing $540 in cash.
Ross also wrote a letter from prison offering bribes and threatening the victims to get the female complainant to retract her written statement to police.
Crown prosecutor Sean Casey argued a five-and-a-half year prison sentence was warranted as a starting point.
That would take into account Ross' prior convictions, which included a 2007 conviction for attempting to pervert the course of justice, he said.
Ross' lawyer Brian Foote argued on a totality basis five years' prison should be the end sentence, particularly given his client would serve every day of his sentence.
Judge Ingram agreed five years was the appropriate outcome despite Ross having a substantial criminal history.
Ross had written a "thoughtful letter" which showed he had some appreciation of the harm he had caused to his family, his children and others from his continued offending, Judge Ingram said.
"It's clear you are well capable of thinking at a high level and to have written a threatening letter in prison to your victims shows a level of stupidity that beggars belief."
Judge Ingram told Ross to think seriously about his future and encouraged him to take up a trade while in prison.
"If you don't get your act together now you are likely to spend the rest of your life inside and that would be such a sad waste of human potential and ability."
