Unless you shattered a piston a rod cannot hit the cylinder wall. Most likely you spun a rod bearing. Which in laymens terms means you need to look for a low mileage long block from a junkyard or the like. Can be had for around $300-$500 depending on where you look.
The balancer is located on the passenger side of the car where all the pullies are located. Look down at the very bottom of the motor and you will see what is in the pic above.
I would still post a short vid of it running so we can hear it. If it's junk then a 20 sec vid isn't going to hurt it further. Or if you prefer, take a look at YouTube and type in "3800 rod knock" and watch/listen to a few of those vids to see if it matches what you are experiencing.
