Cesar Milan will also tell you that calm assertiveness will solve all of your problems. Unfortunately that doesn't actually help you solve your problem. You would learn a lot in a class, trust me.
I pay $100-$120 for a 8 week session, one hour a week. Loki's trainer has a masters degree and is a Certified Pet Dog Trainer. Try basic obedience first before you spend all the money - one home session is NOT going to fix your dog. A lot of hard work and learning how to train and communicate with your dog is going to fix your dog. Trust me. I've probably put over $600 into training Loki (he's now a year and a half) and I'm so proud of his progress. He still has issues with certain things (mostly fear of big dogs) but we're working on that. He and I can communicate I'd say on the level you can communicate with a toddler, sometimes better. He knows a million words and what they mean, and he respects that I'm in charge. He does what I ask. Of course he pushes the boundaries and barks at the UPS man and "talks" back but I get the last word. Trust me, find a CPDT and invest in some training classes. You'll enjoy it, I promise. Loki takes his CGC test in 2 weeks and I'm already looking forward to whatever class we sign up for next.
http://www.ccpdt.org/rstr/DE.html http://www.apdt.com/po/ts/us.asp