Welcome to BP.net!
Temperatures should be 92-94 on the warm side, and 82-84 on the cool side. Your temperatures are too cold for your snake right now. What kind of substrate are you using? Perhaps it is too thick and it's not allowing the heat from the pad to get to the tank. Do you have a thermostat on your heating pad? If not, you need to, they can overheat and burn your snake without something regulating the temperature.
Also.. what are you using to measure the temperatures? The analog dials are not accurate, a digital thermometer is the only way to go. You can get a digital indoor/outdoor thermometer/hygrometer inexpensively at any hardware store or at walmart/target.
Once a week feedings are the norm. Most people feed one prey item that is about as big around as the snake's belly is at it's widest girth.. or a bit smaller. Multiple prey items are fine, but a single one is a bit easier.
Here is our care sheet: http://www.ball-pythons.net/modules....warticle&id=52