Where abouts do you live? You could feed it crickets and mealworms available from the petstore. Be advised however, that if you take it in for longer than a month or two, that it will have a greatly decreased chance of survival in the wild. It would stand the best chance of survival if you release it right away. Chances are that if you keep it for a bit and then release it, it will die. I would release it immediately or keep it for good.