How can I reset the service battery warning?
The bad news is you can not reset the cycle counter, it is a part of battery circuit. Your battery is at its end of life (EOL).

Temperature

How to keep battery running just a bit longer, keep it cold.

Do not have your laptop on your lap even if the name says so.

Go to your fridge and get one of those jelly-packs and put it under the laptop.

Energy Saving

Quit or disable any applications you are not actively using.

Dim the screen as much you can.