wabbitwiki.com
> "They are best kept at temperatures of 55°F (12.7°C) to 72°F (22.2°C)."
Given the context that you're holding her, it is more likely that she is anxious/nervous from being held, causing her to shake.
Re: now being housed in the garage, a single heat lamp and blankets (presumably on the ground?) doesn't sound adequate in my experience of US garages and their lack of insulation. I would take some time to see how you can create a more insulated, roomy enclosure in the garage (while being mindful of ventilation and air circulation, especially if the garage is actively used for cars and such: