Galaxy 2004 Electrical Fault

HELP!!!

My 2004 Galaxy, has been displaying the ABS light for some time, when i had my tyres changed i was told at the garage that it was just the sensor, if i get in the car and the ABS light is off the speedo doesn't work, and the breaks just dont feel right, but light then soon comes on, and all is fine again, hubby has checked brake pads etc, and all fine, but last night...i jumped in the car after my daughters dance lesson, pulled away, applied the brake as i was at a junction, well it was like a disco in the, car?? Fuel gauge was failing to read, then fuel light came on (plenty fuel in the car) then the handbrake light came on, and was beeping all the way home, and during this the ABS light stayed on but speedo wasnt working! so just watched my revs to tell what speed i was doing, when it was convenient i pulled over, switched everything of including the engine, restarted, everything was normal with the ABS light on , then i applied the brake, and it all started again? Typically hubby is now away for a couple of days, and as i live out in the sticks i needs my car?

I had noticed whilst the disco was happening the light for the door locks on the door was flashing, last time that did that i found it was the battery in the key, but its different this time? Any help gratefully received, the car is a diesel and has 130,000 on the clock