Latest member of our family

Two weeks ago as we were coming home one day just before getting to our driveway there was a little beagle standing in the middle of our road. It was very cold out and she was moving slowly toward our car as we drove up. We stopped and picked her up lest she get run over like our previous pet, Cade, had had happen back in March. We brought her home and began to inquire among neighbors if they knew of a lost beagle. She seemed so depressed and cowered so easily that we felt she had been abused and then recently dumped in our neighborhood. To make a long story short, she had no microchip for ID, no collar and tags, she was filthy dirty, had whip and hook worms, ear mites and was thin and dehydrated. We have officially adopted her and named her Windee after our property name of Windy Ridge. The vet thinks she is about 3-4 years old. Now, my question is this:

How do you house break an adult dog?

You can see more pics of Windee and of Cadie on our Flickrs photos.