Low oil pressure

Chances are that the engine is shot from having run so low on oil. Generally, it is best to get big leaks like that taken care of immediately. I know, sometimes life just does not allow time for that kind of thing. Back on point though, if it sounds like there is someone inside the engine hammering away at it, that is a knock. It is probably coming from rod bearings or some, or the rods themselves.

Your options from here are: (1) rebuild the engine - probably cost you $1,500.00 to $2,000.00 (2) replace it with a used engine - probably $500.00 for the engine and $400 to $500.00 to drop it in at the local small time mechanics shop or (3) replace the car.