Fitness trainer Charlene Reaveley, who was originally from Dundee, was thrown more than 60ft into the air and died instantly following the accident in Vancouver , Canada in February 2011.
Cory Sater received the sentence yesterday despite calls from the lead prosecutor for him to be jailed for up to nine years.
Sater, who was at the wheel of a Jeep, was so intoxicated that he was oblivious to the mother of four on the roadside helping the victims of an earlier accident and drove into her at nearly 40 mph.
Mrs Reaveley, who had emigrated to Vancouver when she was seven, was thrown more than 60 feet and died instantly.
She and and her husband Dan had stopped on the city's Lougheed Highway shortly after midnight to help Lorraine Cruz, 26, and her boyfriend, Paulo Calimbahin, after Mr Calimbahin's car crashed. Ms Cruz was killed outright, while Mr Calimbahin lost one of his legs.
Sater, 40, who drove off and his car was found abandoned later was also banned from driving for eight years by Justice James Williams at New Westminster Supreme Court, near Vancouver yesterday. He was earlier found guilty of two counts of dangerous driving causing death and two of drink-driving causing death.
During sentencing, people on the public benches wiped away tears as Charlene's mother, Mary Ogilvie, her voice trembling, read out an emotional victim-impact statement.
Mrs Ogilvie said: "Charlene was my only child. I am a mother now but I do not have my child. Everything near and dear to me was taken away that night.
"I'm haunted by the memories of her being buried.
"She was my only child and my entire world. She's on my mind 24/7. As a family, we are in pain."
She said she still suffered from depression, nightmares, and anxiety, and was on medication.
In a victim-impact statement read by his sister, because he was too upset to do so, Dan Reaveley, who also suffers from post-traumatic symptoms, said he had contemplated suicide, but knew he had to keep living for the sake of their four children, who were 10, six, four and one when their mother died.
He compared Charlene's death to the loss of his sight.
Mr Calimbahin said: "Mr Sater took my leg and my job, but more importantly he took my future."
Ms Cruz's mother said that she felt as if her life had ended.
Sater's trial heard that he had run up a £50 bar bill drinking spirit doubles along with two "Jager Bombs" and other shots.
Prior to sentencing, he told reporters: "There's got to be a positive way to come out of this and become a better person."