For fixing the volume change, here's what I do:
1 - figure out how much you'll be boosting levels of the latter section (the louder one) to bring them up to 0dB (or close if you're of that religion).
2 - figure out how much you'll be doing likewise for the early section (the quiet one).
3 - now find the section of audio where you increased the volume. Hopefully if you evaluate the section just before and just after the change, they'll match approximately the overall difference in #1 and #2 above. If not, start there and begin to play around a bit once you understand what's happening.
4 - Apply a fade out across the section where you increased the volume. For example, if your early levels were about -18dB and brought them up to around -12dB, you'd apply a fade out starting with something like +18dB fading out to +12dB in order to both correct the volume change AND normalize this section.
5 - Then select the early portion and normalize it, and then likewise with the late portion.
For sample accuracy, you'll probably find it easiest to cut up the audio into chunks (three of them in this case) and apply the changes as seperate wave files... which can then be stitched back together.
- Jason