What did they say at the oil change place when they heard the noise? Normally they won't touch the car when it sounds like it already has major engine damage because they don't want to be blamed for it. You may have started out with a "spun" engine bearing. That alone is somewhat expensive to fix but continuing to drive it like that will usually end up requiring a total rebuild or a used engine. Had you stopped the engine as soon as the oil light came on, you would have avoided a lot of repair expense.