I got stop for my temp plate wasnt on the back of my car and when the police stoped me i gave him all the?

paper work for the plate and tell him were it was then he asked me did i have any weed in the car and i told him just a little and he found it i spented 10 hours in jail and paid 1,170 to get my car out impound and now i have to go court for 2.5 grams wat will they do in court on top of that my ex went to court cause the car is in her name and the police lied on me sayin that he didnt ask me did i had weed in the i just told him i had weed in the car and i didnt show any paper work or the plate but the search the car and seen the plate under the seat wat can i do when i go to court since he lied.