Here is what you do....
Go to a place and have the Tint professionally removed (if you know somone at a shop they don't even have to do the work just get a reciept saying that they removed it). Go into court and tell the magistrate that either
A. you took the car in somewhere and told them to tint the windows, they never told you the legal limit and just put it on...you thought you were legal because they did the work and you had no reason to doubt them. Since now you know it is illegal you have taken it somewhere and had the tint removed to be in compliance.
or....
B. You put the tint on yourself with a kit that you got at the local auto store, you assumed that the tint had to be legal since they sold it to you over the counter with no warning, as above you discovered it was not legal via the ticket and you took it somewhere to have it removed.
If they ask why you took it somewhere instead of removing it yourself tell them 1. You did not want to damage your rear defrosters and 2. you wanted a reciept for court to show that you are making a good effort to comply with the law.
if you do opt to remove it yourself or you don't have any friends who own a shop then take pictures of your car with the tint removed, or park it near the building and tell them they can go out and look if they like
Tint tickets seriously blow as they are expensive...good luck.