used car odometer roll back fraud - Toronto, Ontario, Canada

I bought a used car on November 2007 and last month i found out that the car was misrepresented. The person i bought it from rolled the car's odometer back and it wasn't his car he was selling. I talked to him about this issue and he said he has nothing to do with it and he won't refund my money. When i checked the vehicle history report it shows that the car belonged to a dealership. When i contacted the dealership owner he said someone forged his signature to transfer the car to my name. I bought this car as a private sale so i didn't get a bill of sale from the guy who sold it to me. I dont understand what to do. The dealership is telling me that the papers were forged...but why hasnt he done anything about it... Is it possible for me to sue? its been almost a year now...if someone can help me out it would be great

buyer beware !!!!