@Rotorwash: Absolutely right.
Doing SAR myself I can only warn everyone of going beyond your training and experience.
As hard as it may be not to pull someone out of the water right away, I would suggest the following:
If you can (without climbing out of your seat or doing funny stuff like that) drop survival equipment. If available, something fluorescent would be kind.
Most important: Report what happens do an available ground- or even air station. If you can, talk to an RCC or MRCC or Sub-RCC, on guard if you have to.
State your call sign, position, details of the incident, number of persons, state of those persons and injuries if you can.
Stay in radio contact (consider your height)! State your endurance! No reason for you do ditch as well, that just makes it that much harder for the SAR boys.
Land in time if you have to.
If you do that, the rescue is half way over, you´ve taken the Search out of Search and Rescue.
Thomas