Car Theft Charge After a Car Sale Fell Through

My question involves criminal law for the state of: New Jersey, Camden County
My boyfriend and I are facing 3rd degree theft of a vehicle.

My boyfriend and my brother made some deal for his car, but I guess he changed his mind and refuse to give up the bill of sales. Upset that he put out money for a car he couldn't drive my boyfriend decided to just sell it for parts on the internet.
There was a huge argument and the cops were called. My brother was arrested for assault with a deadly weapon. A week later my boyfriend and I was arrested for the theft. I was charged with co-conspirator.
The vehicle is a 95 Miata and worth $1500 on Kelly blue book at excellent condition, but my brother is claiming it's worth $50,000 because of upgrades. My brother was able to get his car back from the buyer that it was sold to.
We spoke with a public defender but they didn't give us much information. The case was then sent to our local municipal court but there was a huge confusion as to why. We spent 8 hours in traffic and petty crimes court to just be assigned another public defender for municipal court.
The prosecutor seemed like a hard ass and told us that we were facing very serious charges. This is a first offense for both of us.
My brother buys and sells a lot of cars on the internet and I don't know what kind of proof he has that the car was worth $50k. I can't imagine he even has 50k, but I'm not the judge.
We can't afford a lawyer. We have a new court date and was told in a letter that our public defender will see us before the trial. Will we be looking at jail time? What would we likely be charged and what's the worse?
Thanks for you time and advice.

You have an attorney, you should only be dealing with him - not an online internet forum.

By the way, unless it is gold-plated I cannot see any Mazda being worth anywhere near $50k.

I'm not sure why you are getting wrapped around the axle about the valuation of the car. As long as it is worth at least $500 you are in SERIOUS truoble. The ADW is pretty darned serious as well. You post is missing any details that would giave any indication as to a defense. But that's good, we DON'T WANT THE DETAILS NOW. Listen to your attorney.

I hate to break it to you, but you're going to find your self sitting in court a few more times even if this gets resolved in your favor.