ok I ripped a dvd using Avimux to put the sound and video together but its really quite, and I have to turn my stereo almost all the way up to hear it.....I'm not that good with the whole sound thing.
DVD audio is quiet by its nature (it has dynamic compression).
The only way to boost the audio would be to recompress it and normalise it. You can read about that in the guides.
Alternatively, if you ware using AC3 audio you can download AC3Filter from doom9.org and set the boosting and normalisation settings to hear it louder.