"This is a 77-year-old man who has been incapacitated by a blow to the head and neck. He was vulnerable and she set him alight," Crown prosecutor Warren Cathcart said.
"This has been carried out by a calculated mind that contains no pangs of conscience."
Justice Rebecca Ellis said it was unclear whether the head injury, the fire or both had killed the victim.
Only hours earlier, the offender - who whimpered throughout today's hearing - had set a tissue box alight and placed it underneath Mr Dixon's bed.
He woke up and put out the fire and the woman told him it must have been burglar.
Mr Cathcart said further aggravating the offending was the fact the offender deactivated smoke alarms so others would not be alerted to her actions.
Justice Ellis said the woman's actions could be partially explained by a history of sexual abuse and subsequent mental health issues, however the victim was not the perpetrator of those crimes.
The woman was also sentenced on four counts of arson, one of attempted arson and four charges of theft by a person in a special relationship - amounting to $12,500.
Most of the charges related to offending between November 2011 and January 2012 at the woman's workplace.
It was initially thought the blaze was accidental but police said the charges against the woman came after a "lengthy and complex" police inquiry.
She denied the offending through several police interviews before pleading guilty three weeks before her trial was due to start.
It was revealed in court the woman had struggled with post-traumatic stress disorder, depression and anxiety.
She covered her face as the judge passed sentence and sobbed into her hands as she was led away.
A packed public gallery also cried during proceedings and many had to leave the court when the grisly details of the murder were outlined.
