Second hand car dealer refuses to repair Car.

I purchased a Jeep Cherokee 2002 model 3.Lt petrol 3 months ago from a second hand car dealer in Brits, named Ref's Auto ***. About a week ago I had a major breakdown on the vehicle, it concerns the cylinder head, which has to be replaced. The cost total an amount of R15000.00 spares and labour. The owner of the dealership where the Jeep was bought refuses to share any responsibility concerning the repair of the vehicle. I have driven it for 3 months. I believe this is not fair towards me, since I am a lady driver, the Jeep was never misused. Please, can anybody help?