How would i know if I slung a rod threw my motor?

So i was driving home the other day and everything seemed good with my car (I just bought it used as is, no warranty, and no refund 2 days before the accident) but i had noticed that my oil was low so i put a quart in it (castrol 10/40 because that's what kind my car takes...my car is a 2000 dodge intrepid if that helps) then after i added oil it was still a little low but nothing to really worry about. The next day i was noticing my car was kind of jumpy feeling when i was going up a hill or stopping. Then a little ways down the road after that i heard a pow and something black fly across my windshield (i thought my tire busted because it was knocking and shaking). i pull over and my tires are fine so i open the hood and the serpentine belt was fine. there was smoke coming from the right back side of my engine. i checked my oil and it was showing i had too much whereas the day before it was showing i didn't have enough...well there was oil leaking everywhere and it was still showing i had too much oil. so did i throw a rod or did something else happen? the car still starts but it makes a knocking sound.... if it is a rod how much do you think the mechanic bill would be?