It seems to me that you have several issues to address:
Who sold you this car and did you get it inspected prior to purchase? You may have grounds against either or both of these parties as it appears they may have let you down a tad here.
Pull out your extended warranty and get very informed as to what is supposed to be covered. Insist that all that should be covered WILL be covered.
On the face of this, you are either very unlucky, gullilble (hope not) or you have been had.
Try to figure out which and if you can, seek some redress.
Keep asking questions, we are here for you!