Roisin O'Neill, 24, plead guilty to homicide by vehicle while driving under the influence in Montgomery County court on Thursday morning. She was sentenced to five-to-10 years in state prison.
The crash happened on September 12, 2008 on Route 476 in Plymouth.
Investigators said O'Neill, of Newtown Square, was driving the wrong way in the southbound lanes of the Blue Route, slamming into an oncoming car.
Patricia Waggoner, 63, of Massachusetts, was killed.
Family members said she was on her way to see her grandchildren in the area.
"Each day I wake up and I'm reminded I've taken an innocent life. I am beyond sorry for causing so much pain," O'Neill said as she addressed Waggoner's family.
As she was leaving the courtroom, O'Neill was asked if she felt relieved.
"No. No, I don't feel relieved. I'm just sorry for everything that happened, and you can't take these kind of things back," she said.
Waggoner's family was also in court. They read impact statements to illustrate just how much they've lost.
"It's a lot of misery, just needless misery, and I just feel awful," said Al Romanelli.
Investigators said O'Neill had a blood alcohol level of more than double the legal limit.