I can suggest 2 things:
- either continue using SubAdjust using the guide for it that you can find
here
- or use the tool
SubSynch which is much easier to use: you can shift all the subtitles, stretch them, and if you need fine-tuning you can just watch the movie on the included player and press "space" whenever you want to add a subtitle (as long as you keep it pressed, the subtitle will appear in the movie). Try it!
Cheers, Smarties :P