If you want out of the sale at this point, you'll need to take the seller to court.
If you don't feel like you can build a case for non-disclosure, consult an attorney and decide whether to proceed with a suit.

I assume the title still shows the bank that initially financed the car..
If so, it's questionable whether the person you bought the car from had legal possession of the car in the first place.

Also, the fair market value of a salvage titled car is absolutely decimated.
Sight unseen, the best you could manage IMO is $2500... and that's with the current problems resolved. If you decide to make the repairs and use the car, do so knowing that you're best off keeping the car until it is fit only for the scrapyards.

No matter how this resolves itself, never buy a car without confirming the status of the title.
The time & money spent at the DMV to check things out beforehand is a pittance.