NO JOY FROM DEALERSHIP

I have purchased a vehicle from a dealership(Group One Auto) in Centurion on the 17-12-14.I traded my car in as a deposit for the vehicle.After 17 days of driving with the vehicle,I noticed that the gears became sticky,car started smoking,aircon packed up,foul smell coming through the vents,car started idling irratic.I contacted the dealership to notify them about the problems,in turn they said that I have to bring the car in for inspection in January 2015.After they had their mechanic look at the car,they said that its wear and tare that's the coarse and that they would not help or assist me with the repairs of the vehicle as I bought the car\AS IS".I'm now stuck with a problematic car and have to pay R2000 pm installement for 27mnths"