nightmaRe

i have a 97 car ran great, i let it sit 2 months now its all jacked up. car is over heating and leaking antifreeze out of the front of the motor. also the exhaust has a hole in it making the car sound like a monster truck. checked for codes reported the following.

1. misfire cylinder #3
2. H02s 12 circuit condition (heated oxygen sensor bank 1 sensor 2)
3. target idle speed not reached (idle air control motor circuit/iac valve)

is my water pump bad? any ideas? and i am gonna get the exhaust patched. thanks in advance.