On November 18, 2014, McAllister knocked on her ex-partner's door and hid from view.
When the new partner came to the door, McAllister burst inside and attacked her.
She punched her in the face, grabbed her around the throat, and pulled her by the hair to the ground.
McAllister then straddled the victim and used both hands to choke her. The victim fought back before McAllister pushed her face into two walls, punched her again, and kicked her several times in the face and stomach.
McAllister then went to the kitchen and got an 18cm knife, held it to her face, and told her to get out.
The victim, who had serious bruising and swelling to her face and head, ran to a dairy and phoned police and an ambulance.
Ahead of a three-day trial due to start this morning, McAllister pleaded guilty to the amended summary of facts after an attempted poisoning allegation was dropped.
The Crown said there was no evidence on a charge of causing a woman to take a "noxious substance", namely Seratine and Nurofen, with intent to cause grievous bodily harm.
Judge Alistair Garland thanked the jury panel for coming to court even though the trial didn't go ahead because of the late pleas. But the judge said their attendance was not for nothing, as their presence "rather tends to concentrate the mind of some people".
Judge Garland remanded McAllister on bail to be sentenced on November 9.
He warned that home detention "might be optimistic" given the seriousness of the aggravated burglary charge.
However, he did call for reports to consider the appropriateness of a home detention sentence.