Training an aggressive puppy?

My family and I have just gotten a puppy from the pound named Bella she is about 11 to 12 weeks old. She is a VERY aggressive puppy, anytime you walk across the house, if you pet her, if you pick her up, or if your sitting on the couch watching t.v she will attack you. When we took her to the vet they told us that she had a very dominant alpha personality and she is much stronger then an average puppy, she bites down a lot harder, and that she is a very smart dog and for us to try to use aggressive training-but that didn't work at all so we went back to doing positive reinforcement with training treats and the little dog clickers and it works just a little bit more but currently we are still getting attacked-and it hurts a LOT. We have already signed her up for obedience training but that doesn't start until next Saturday and even that is going to be a long, hard and slow process. At my home we frequently watch the dog whisperer and we try to stay calm but firm and I have also read to of his books but none of it seems to work with Bella and we really need to nip this in the but before it gets more out of control. (They know she is a lab but they think she may be mixed with either a boxer, a jack russell terrier, both, or something else entirely)