I have been ripped off by a car trader (suprise) Help!?

Hi I bought a car from a second hand car dealer about a month ago and have just had my v 5 document come through and have found out is not a '1 owner car' as advertised but I am in fact the 3rd owner. Is there anything I can do to get back at these con artists? If i had known it was not a 1 owner car i would not have bought it as it had no history - and now it seems I have paid way over the odds. any help much appreciated.