1999 Daewoo Lanos no acceleration

Engine Performance problem
1999 Daewoo Lanos Front Wheel Drive Automatic

my lanos 99 struggles to accelerate. It used to be just when reaching the higher speeds, but now suffers across the whole range. In top gear it judders as if it is only getting something part of the time. In most of the rest it takes a long time with high revs before changing gear as it struggles to accelerate. Its even started to judder when idle. It had a new battery a couple of months ago, and that seemed to stop the high gear judder, but now its back and worse! Any ideas as to the cause and how we may fix it!