Much as I love cats, in your particular case, it may not be a good idea to adopt that stray cat or any other stray cat.
First, you already have a dog and a bunny rabbit. That's already quite a handful. I am assuming that you are an average person living in an average-sized house. If you really want to help, you can just bring some food for the stray cat. If you can afford it, take it to the vet to be vaccinated and spayed. Then put it back where it came from.
Yes, it's adorable. Yes, it's seems so cold-hearted to just let it live there in the open. But have you thought of the dog and the bunny rabbit that you already have at home? Have you thought of the adjustments they have to make to accommodate the stray cat if you were to take the cat home? You love the dog and the bunny rabbit, don't you? And the dog and the bunny rabbit love you, too, don't they?