Firstly, You have to go to traffic department and pay the fine and say to them about the car than you might get it?!?!?!

You can know how much fine you have to pay by simoly going to website of

moi.gov.qa --and then go to traffic violation and write the plate number of your car and than you can see the fine....

Again you should not do that because government is taking serious action against those who are driving private taxis....