You have my sympathy, I have been trying to respond to your post for days and everytime I sit down to the computer (or to my knitting for that matter) our new puppy (7mon old SPCA boxer mix) decides she needs attention.
When we got Daisy we were her 4th home and she had been on a leash 2x. Not only did we have to housebreak her, we also had to convince her it was okay to go on a leash. I went to the fabric store and bought webbing for $0.75 yard and basically made a lunge line so she could roam away from us and everytime she went outside on the leash and did her "potty" she got a high value reward (piece of hot dog, string cheese, or liver treat) and if she went in the house she got ignored.
It takes a lot of time, patience, and lost sleep, but they are so worth it
Best of luck and keep up the good work.