Caring for a Three Legged Dog or Cat

I live in Idaho With my Husband and Daughter. Three Years ago Harley came to us in the middle of the night. It was raining and He was soaked and muddy. I took him in and gave him a gave him a bath and let him sleep on my bed because he wouldn't settle down otherwise. We tried for the next month to find his owners but to no avail. So we adopted him into our family. he has been a very active dog. He hardly ever wanted to lay down and he followed me every where. If I wasn't there to follow he would find who ever was available. About a month ago we took him in because his leg was hurting. He had a large bump that the vet thought it was a spider bite and was going to go in to drain it. We got the call with in an hour that Harley had a bad tumor on his leg and the vet would have to take his leg. We were really heart broken. It would be a big change for Harley and for us. The vet said that he thought he got most of the tumor and sent us home with Harley. We have been positive for Harley. He seems to be doing really good.