about buy a garbage car

i buy a car from a big dealer,befor i buy this car,ialready let automobil check.it said ok for every check.then i buy this car.after nearly two month,i found some problem,then went to check-big problem,if repair ,need a lot of money.
what should i do?
can i sue dealer and automobil to repair the car?
(i did not buy worrenty,that my stupid.can i buy now?)