A good behaviorist/trainer is a must I think.Doing the wrong thing can do more harm than good and taking it to fast can be just as bad,one setback can ruin weeks of work..It is to hard to tell you exactly what you need to do never meeting and obseving the dog you need and expert to see your furbaby and ebaluate Nicky.You will be amazed what you can accomplish with individual weekly work with a good trainer,please,please seek one out and get Nicky the help needed. I almost forgot where are you located maybe someone knows a good behaviorist/trainer in your area.You can also ask you animal rescues in your area and your vets and people with well trained animals that you trust and respect who they trained with.
Laurie