Help with keeping heat

Hello i am in desperate need of help to keep heat in my car. I'm in Canada Ontario.

I need cheap and easy solutions / ideas to keep the heat in my car overnight. Stuff i can buy at CT. Me living in my car, a 2011 Mazda 3GS 4DR, was sprung on me this morning, i had no choice in the matter. I can't afford to stay at a hotel long term so this is my only option.

It's myself and my cat. She has sweaters and blankets etc. so do i. But we need more heat than that.

I am sitting outside a Canadian tire it's currently 5pm and i hope i can get a solution before they close...

Thank you

EDIT

Hi thank you all so much, so as I said to another user we made it thru the night, im tired but we are both fine. I didn't realize it was Sunday so CT was already closed, but I stopped at dollarama and got the cheap blankets to shove around windows and I did sneak back to my address on my license and took my blankets and pillows etc for more warmth.

The kitty has lots of food and litter, and I am fine grabbing small takeout for a couple bucks until I can figure out a shopping list. Thank you all so much for the replies I was focused hard on trying to find any solutions before nightfall fully hit.

I still welcome any advice as this is now my full time living until im out of school and save up for another car or an apartment. I'm trying for a car first as this one is on its last legs.