Her charges included five counts of forgery, five of using a false document and 15 of dishonestly using a document.
According to court documents, the woman used the money to splurge on concert tickets, high-end designer clothing and general household items.
Judge Taumanu said Boyce ran eight "distinct" schemes over the period of her offending which involved sophisticated invoicing arrangements.
One of the schemes involved putting her bank details in the place of another company's and invoicing MediaWorks.
"You were in a position of trust," Judge Taumanu said.
Initially, the motivation for Boyce's offending was said to be motivated by a desire to fund her lifestyle but following a number of reports, the judge said there were "clearly other mental health issues" which contributed.
Judge Taumanu gave her a six-month discount from a starting sentence of 4.5 years as well as a guilty plea which saved what would have been a lengthy process of the Crown proving all 25 charges.
He sentenced Boyce to three years' in prison.