I'm in law school, not a lawyer yet, but am almost there. This is my personal advice to you. What you need to do is find and pay out the ass for the best defense attorney you can find. One of the main things you're looking for is experience. The following website lets you search for a lawyer and lists things like experience and education.

Nolo's Lawyer Directory - Meet Your New Attorney

NORML's website lets you look for marijuana friendly lawyers also. But I'm not sure if they screen for experience or not. If you go with one of them, make sure to search for their experience too.

I have a strong feeling that a good lawyer could get your case tossed out simply because you did not consent to the search. In saying he smelled MJ the cop is basically saying his nose is better then the dog's... which is complete bullshit. Perhaps your lawyer could even attack the original stop in the first place.

Even if you can't get out of the stop or the search, a very good lawyer could likely plea to get you a lot less then what you're currently looking at (especially if testimony can establish the history of your automobile). It will be expensive and time consuming, but worth it if you're looking at jail time.