2006 Pontiac Pursuit Electrical Problems (Need Help ASAP)

Hey guys, I happen to own a 2006 Pontiac Pursuit and it runs fine majority of the time but sometimes there is a major problem with it. I'm fairly positive its an electrical problem.

So.

The T/C light, Power Steering message, Check Engine light show up on the dashboard. My steering becomes manual pretty much and I have no electrical help what so ever. The car jerks when the gears shift. My instrument panel lights up with all the faults for a split second and if I slow down too fast by applying the brakes, then the car shuts off. My stereo volume also starts to go up and down if the have the auto volume on the high setting and my speedometer needle goes 20-30 km/h above and below my current speed.

If someone could help me figure out what the problem is I would really appreciate it.

Thanks