The prisoner then went to a nearby shed and came back with something hidden behind his back, which the victim believed was a knife and feared for her safety.
As she walked into the lounge August produced a plastic spray bottle from behind his back and sprayed the left side of the victim and her hair with a petrol-smelling liquid.
Stunned, the victim tried to move down the hallway but August quickly moved in front of her holding a cigarette lighter.
In frustration, the victim grabbed the lighter and told August "she would do the job for him", and flicked the lighter on the left sleeve of her top which ignited, the court heard.
Flames quickly moved up the victim's arm and August pushed her to the ground, put his full weight on top of her and pulled the top over the victim's face and head.
The panicked victim, who felt she was being smothered by the top and the flames coming up her arm towards her head, yelled out to August that she was on fire.
The accused ripped the top off and told his victim "you deserved it".
August left the house but returned a short time later to apologise but left again and walked to his sister's home and told her what he had done.
The victim called the police after she ran water over her arm.
Her left arm and ear were blistered with burns and her hair was singed.
August's lawyer, Taryn Bayley, argued that an end sentence of four to four-and-a-half months in prison was appropriate after allowing August a 25 per cent discount for his guilty plea.
Judge Cameron agreed but noted August had an extensive criminal history which included an aggravated robbery conviction in 1996 for which he was jailed for five years.
August had other convictions for assault on police, obstructing police, dishonesty, drug-related offences and several drink-driving convictions, the judge said.
This would be August's first conviction related to family violence. However, there had been early reports to police about family violence incidents, the judge said.
Judge Cameron said the victim said in her victim impact statement that she had forgiven August but did not want to resume a relationship with him.
While August did not set fire to his victim this incident had "very sad consequences' for her, and there had been no particular expression of remorse by the prisoner.
"Nevertheless this was a most despicable act for the defendant to carry out which carries with it attendant risks," Judge Cameron said.
On his release from prison August is subject to six months' release conditions which include his completing a family violence programme and other counselling if needed.
