Dead Battery?

Every now and then we used to start the car and the steering would be a little on the heavy side for about 30 seconds.

Now gone to start the car this morning and basically it was dead, managed to jump it to get it started, 1st click away it goes but the steering was heavy and the light was on the dash.?

i've heard of it being a problem with power and just wondering if it would be the battery thats doing it? as when the car was stopped it needed jumping again. everything seems to be where it should just wont start unless jumped.

Thanks For looking!