I'm not sure if his shows are available online or on on-demand but The Dog Whisperer had a show about stopping a dog that was marking everywhere. the show is on Animal Planet. That might be of some help. (We don't have a dog but DH is addicted to the show.
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Please be very careful with this. I have seen many dogs that, using his methods, would push them to bite. Being a puppy mill survivor, I don't know how social he is. Some puppy mill survivors are amazingly outgoing and friendly considering what they've gone to and others will go and hide, shaking in a corner. Depending on the dog, using his methods may cause more problems than helping.
They sell things called calming collars that have natural pheromones in them. They work wonders on my cat that has issues with using her litterbox and I have spoken to several people that use them for their dogs that swear by them. You may want to check thosse out.
For the barking, try putting it on command. When you put it on command, then you can also put "Quiet" on command. When the dog is barking, say "Quiet" (or whatever you want to use) and remove them from whatever is making them bark. When they stop barking, give lots of praise. My dog had barking issues and I got her to "Tell me!" on command and then "Quiet" on command. She still barks, but it is so easy for me to get her to stop now. I also try to teach all the dogs in the shelter I work at "Quiet". People are always amazed when a bunch of dogs are barking and I say "Quiet" and the whole row of dogs goes silent and looks at me. You can also try putting coins or pebbles into an empty pop or soup can and shake it and say "Quiet" everytime he starts to bark. This will hopefully startle him just enough for him to lose focus and get distracted from barking.
As far as marking, marking and not being housebroken are two very different things. If he is just urinating in the house, then he is not housebroken and that is what you need to work on. If he is truly marking (maybe he urinates outside and then comes inside and marks a small amount on the wall), my first question is is he neutered yet? If he isn't, that needs done ASAP. Are your other dogs spayed/neutered? At 3, if your other dogs aren't neutered and he recently got neutered, he will probably keep doing it just because he has been for so long. How long has he been neutered if he already is? It will probably take some time for the hormones to go down and until they do, he very well may continue marking. Make sure you correct him everytime you see him start to look like he is going to mark. Don't even wait until it happens. If he goes up to a wall, sniffs, and even looks like he's going to lift his leg, give a stern "NO" and clap your hands or make some other loud noise, again to distract him.
