Rescued a Jack Rusell and need a little advice please?

About 3 months ago, my family rescued a Jack Russell/Westie mix. He's estimated at just over a year old and had probably been in the kennel/rescue place for about 6-7 months (estimated). When I picked him up, while all the other dogs were let out of their cages on leashes with volunteers, this little guy, now named "Ares" was in a cage sitting next to a fence. They said it was because he was too "out of control and wild". After talking to the head of the rescue group, she said Ares had to be secluded because he bit a high school student volunteer who riped his dew claw out when he was removing the dog from the cage.

Ever since I picked Ares up, he's been really loyal and friendly to my family and my boyfriend's family, but he hates the rest of the world. I don't understand it. If we have company over at our house, he growls and gets super excited like he wants to say "hi" and greet the person entering the house but when they get close, he attacks. It's worse when people come to the front door (but both of my dogs kind of realize that friends use the garage). Ares growls at people when we're out on walks, and sometimes if another dog starts to approach me, he'll get all defensive and start pulling on the leash and jumping. I use a Halti when walking him, which makes an improvement, but everytime I go down to our town park there are always people who leave their dogs off a leash (even though it says "ILLEGAL DOGS MUST BE LEASHED AT ALL TIMES") and we usually get attacked by other bigger dogs. I mean I understand that Ares is trying to protect me, but is their any behavior training I can work with him on?

Another problem is that he gets so wound up and excited that he's almost ridiculous to calm down. Even if secluded, he'll just destroy whatever room he's in, chewing up everything, running wild. I've talked to my groomer (who is also a breedre of Kerry Blue Terriers) and she said it's ok to put Ares on tranquilizers or low dose ADHD drugs, cause her terriers are on them, but my vet says he won't perscribe them. Actually Ares bit my vet because he got too close to me. I know he's still a puppy, but he's been labeled as "too agressive" to enter a group basic training class and I don't know of anywhere that is relatively inexpensive to work with a "problem" dog.

I'm kind of at my wits end here since some of my family members (outside of the people who live with me and Ares on a daily basis) as well as neighbors say that Ares can't be helped and we should just put him down or give him back (although the rescue group I got him from is no longer in existance) He's not a bad dog, he's just been in a kennel/rescue group for so long he hasn't been properly socialized. I'm not ready to give up on him, but I need a training solution for when I have company over; he can't be trusted outside of a cage.

Any suggestions for what I can do. I live in Buffalo, NY. I'm willing to do whatever it takes and money really isn't an issue, but If you know of someone in my area who works with problem dogs that would be great. Thanks in advance.
Thanks for the comment "It is the behavior of a possessive/aggressive, territorial, poorly socialized dog. Period. End of story.". I think I already said that when I rescued him we knew he was poorly socialized, being in a kennel for 6-7 months with minimal volutneers, I think I did the dog a favor.
Thanks for the advice. The dog is definitely getting enough exercise, we have a pool and a treadmill (although the treadmill thing doesn't quite work, he's afraid of it). I'll post on the other site and see what help I can get there
IMO, you are dealing with a fearful dog, whose fear is being expressed through aggression.

I really think you need a professional to help you with this (unfortunately I am not in your area, so I do not know of anyone), but there are two things I would do differently, right off the bat.

First, I would only walk him in areas where you can be reasonably sure that you will not encounter loose dogs. Being attacked by other dogs is not going to help his attitude.

Second, if you have some way to wear him out, physically, then that might help.
Treadmill, swimming pool, bike (where there will be no loose dogs)….something like that. JRTs are known for being very high energy dogs, and that is complicating the situation.

At this point, I would continue to crate him elsewhere when people come to visit.

Here is the address of a forum for problem dogs. Why dont you post there, and see if anyone can recommend a trainer in your area?

http://leerburg.com/forums/ubbthreads.php

EDIT:
Treadmill training is not hard……I have taught several dogs. My treadmill is against the wall on one side, so I can stand on the other side. I put a leash on the dog, and start out at 1/2 mph.

If necessary, I hold the dog on it until he figures out that he can walk (some try to lie down). If the dog jumps off, I just calmly put him back on without stopping. Once he is comfortable walking, I slowly increase the speed.

Sometimes I use cheese to make it more attractive .:o)

Once the dog learns to walk steadily, I start the treadmill first, and then ask him to walk up onto it from the end while it is moving. For some reason that seems to be easier than starting from a dead stop.

I usually start slow, ramp up, and then cool down again. With the hyper dogs I have had, I found that two 20 minute sessions a day seemed to work better than one longer session.

Be sure not to leave the dog on the treadmill unattended.