Amanda Charlene Haley said she was supposed to be driving to emergency housing to escape her abusive ex-partner when she drove onto the wrong side of the road at Forresters Beach on the NSW central coast.

She pleaded guilty to aggravated dangerous driving causing the death of Angela Gillfeather, 67, and causing grievous bodily harm to her husband Glenn Clarke, then 65, on January 25, 2020.

The then 37-year-old mother, who was substantially impaired by the drug ice at the time, also admitted she was driving during her third period of disqualification.

In the Gosford District Court on Wednesday, Judge David Wilson jailed her for five years with a non-parole period of three years.

She was seen driving erratically behind the wheel of a Mitsubishi Outlander before colliding head-on with a Toyota HiLux driven by Mr Clarke.

Ms Gillfeather died in hospital after emergency surgery, while Mr Clarke suffered very serious and long-lasting injuries as well as the trauma of losing his wife.

The judge accepted Haley suffered from substance use disorder and borderline personality disorder, the latter having some connection to the offending.

At her sentence hearing, she testified to having left her abusive partner who followed her to a friend's house and threatened them all with a knife.

She had slept in a car near a beach that night, before smoking ice and setting off to collect a set of keys to emergency accommodation she had organised through a domestic violence hotline.

But she instead drove in the opposite direction and was seen "undertaking" cars, going faster than other drivers and crossing double white lines before crashing into the Toyota.

She said she had "no idea" why she had been travelling in the opposite direction and admitted driving under the influence of drugs many times.

The judge, who found her to be a credible witness, accepted she had shown remorse.

Her mother testified that Haley had "zero capacity to function" in the year before the crash due to her ice addiction and the domestic violence she experienced from her ex-partner.

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Australian Associated Press