The woman went to the pound on Friday and adopted the dog.
Mystery remains as to who had the dog after its owner died, and how it got into the car - whether someone smashed the window and put the dog in, or whether the dog somehow jumped in itself.
Cobain had posted a photo of the dog on Facebook page Buy Sell Swap Wanganui, and later received text messages from an unknown number saying "Got my dog bitch" and claiming they were coming back for the animal.
Nobody answered the phone number when she rang it and nobody came back for the dog, which had already been taken to the pound.
Houlahan said it was a "happy ending" for the dog to be reunited with its old owner's family.