Chefbasha, from your post, I guess the head gasket might have damaged due to overheat. If you were using the vehicle at the time of incident, you can decide what and how the service needs to be done..!

If you found the head gasket issue immediately after the incident, you can say the rings will be fine and no need to bore/replace it. Because the pistons will be safe. If the rings stuck inside the chamber, and there is a play more than 3-4mm, better change the rings/piston. Note: The speed is a factor at the time of the damage.!

Next, the service cost.
Try finding a new/ re conditioned engine for around 4-5K with two weeks guarantee and avoid all service headaches. Just give the damaged engine + cash and get the new engine. Its the easiest part.

If you decided to service the engine, be sure you are at the right place. The wrong team will make the task a disaster. The service will be at your own risk. No one take risk if any issue after servicing. Be careful. If you found a place, be sure you are there at the time of opening the engine. (I hope you have some idea about V6 engines).

I am sure, if its the problem of just overhauling it will cost you around 3500 to 4000 including labor.

Best of luck.

RR