Wheelchair-bound Sarah Thompson feared Roslyn Galas, 42, would break her neck during the attack at her home in Greenend, Salmesbury.
Miss Thompson was so frightened that when she struggled free from her attacker, she trapped herself in the lift so she could call for help.
Galas was arrested on suspicion of attempted murder but the prosecution accepted a guilty plea to a lesser charge of assault occasioning actual bodily harm (ABH).
Preston Crown Court heard the women had met on a dating website and Galas, originally from Birmingham, quickly moved into the home in Lancashire.
Soon after, Miss Thompson - who has tetraplegia - learned she had been unsuccessful in a civil claim against the NHS and became depressed.
From that point, Galas became cold and verbally abusive, the court heard.
In November 2105, Galas texted her mother telling her Miss Thompson was going to take an overdose - a lie which Miss Thompson asked her to put straight.
But the following day, while Miss Thompson was upstairs having a rest, Galas came into the bedroom and started being affectionate towards her.
When Miss Thompson asked if she had spoken to her mother, Galas snapped and took a cushion, which had been on the sofa downstairs, and put it over her girlfriend’s face.
Miss Thompson, who is completely paralysed in one leg and has nerve damage to all her limbs, wriggled free, but Galas put her hand over her mouth and pinched her nose.
As Miss Thompson fell to the ground, Galas punched her and took hold of her neck, pulling it backwards.
Recorder Mukhtar Hussain, sentencing, said: “She had the clear fear you were trying to break her neck.
“She describes how frightened she was and how she was trying to manage controlling you, given her limitations.
“She managed to do that and she managed to go into the lift to get away from you.
“Once she was in the lift, what followed speaks volumes.
“She stopped the lift halfway between the ground floor and first floor so that you couldn’t get to her. She had the controls of the lift in her hand so the lift could not be operated.
“She then rang her brother who lives in Sunderland and he called the police.”
Miss Thompson had bruises to her neck as a result of the attack.
The judge said the attack was premeditated as Galas had taken the cushion upstairs to where Miss Thompson goes to sleep in the afternoon.
He added Miss Thompson was particularly vulnerable due to her disability.
The court heard Galas has no previous convictions and cares for her mother who has a serious illness.
Recorder Hussain jailed her for three years and ordered her to pay a £120 surcharge to the court.