WHAT SHOULD I DO WITH THIS POOR DOG?

Everyday on my way home from work I drive by this one house and they have a very small black dog. I cannot tell you how many times I have seen this dog running out on the road near the main road where there is alot of traffic! I even stopped one time because it was chasing its owners car down the road almost to the busy hwy!! I have caught it before and gave it to the owners... Well today I was almost home and guess what I see trouting down the middle of the road about 1/2 mile from his house??? THE DOG.. I opened the car door and grabbed him.. He is now home with my family but has a bad back leg...he cannot even be a yr old.. He has A COLLAR AND TAG WITH HIS NAME<