1.0 6N2 cutting out HELP!

Hey I could use some help!

On my way home yesterday My battery light flickered on a couple times then went out so I thought nothing of it, A bit further down the road My Handbrake light started flashing and my ABS light came on, Also a loud beeping noise. I was almost home so I just carried on. A little while later a guy in front of me was turning into a lay by so I took my foot off the accelerator to slow down, as I did this the car juddered then lost all power, I put my foot down but nothing happened. Made a beeping noise again and the air bag light came on.

I managed to get it onto the side of the road but it wouldn't start, didn't even turn over once, when i tried the clocks vibrated and reset the time and miles each time.

Had to get my Dad and his T4 to come and get me, managed to get it going again with jump leads and got home.

I went up town and got a new battery and this seemed to fix the problem. Until the way home today, the same thing happened 4 times! as soon as I ease off the accelerator or apply the brakes! Loud beep and the ABS, Handbrake and Air bag light came on seconds before, had to jump start it again each time!

Battery just isn't holding any charge.

Really have no idea whats going on, completely wasted that money on a new battery! could it be the alternator maybe?

Its going to the garage tomorrow and hopefully my Dads mates will sort it out. Nothing too expensive I hope. Having a new clutch put in next week as the biting point is literally a cm or 2 away from not even touching the pedal! Stupidly high and slips now and then. Could it be related maybe?

Please help me guys, Thanks a lot, Dan