It looks like a mid-'90s Buick Century wagon. Below is your photo enlarged and brightened so you can see the car better, and below that is a photo of the back end of a '96. This one has woodgrain, but the taillights, back-up lights, and bumper are pretty much identical.
By the way, as you can see, only the word "Buick" was on the back. The Century name was on the side at the rear.
Sweet, really sweet. This image catches what life in 1950s America meant to so many. Someone had a young daughter who could be clothed in a pretty new dress and saddle shoes, a new two tone Buick hardtop and a bungalow in the suburbs. If you lived thru the poverty of the 30s depression and all that WWII brought this must have seen like heaven on earth and it is all right there in kodak snapshot.
I expanded this, and now wonder if that's Katherine Hepburn? I don't think so, but there is one part of me that thinks so.
At first look I thought no way it could be Hepburn. Not with that hair. Enlarged photo like Silvertwinkiehobo did and now see the resemblance. Another mystery woman.