poor service of a car dealer

i didnt even whant to give a star service is poor we buy cars in silver lakes sold me a car witch obviosly has problems but acording to the decra report it was minor problems when i drove the car home i wated until a available worksop could fix those minor problems only to find out the top gasket is blown and many more costing almost the same as the purchase price i then wanted to return the car and the salesman was of no help they put another customer as an excuse to help you right away what do i do about this it is a lot of money just to throw away