Portal 1 Sounds in a portal two map?
Is there any way to do this?
I'm mainly only interested in the glados lines.
but the music and such (the ending song in particular) is important too.
Yeah, it is definitely possible!
You would need to be able to extract the audio clips from Portal, and then place them in the sounds folder in Portal 2. Unfortunately I do not know where the sounds are stored in the original portal, so hopefully someone with the know-how will come along 
.
In the meantime hopefully it's some comfort to you knowing this is possible.
You can't extract the voice lines for Portal 1 here, but here is the list of them all put out into their different audio files, so it is easier to identify the ones you want when you find where they are stored:
http://theportalwiki.com/wiki/GLaDOS_voice_lines#Portal_2
Just scroll your mouse over the line in blue, and it will tell you the name of the audio clip in the files.
Goodluck!
Actually I lied, just right click the lines and choose save target as, then save it in the sounds folder of portal 2. These are wav files however, so they are a bit big. I actually did this to make GLaDOs say "Hello, and again welcome to the Aperture Science computer aided enrichment center, when I log on, and Goodbye, when I log off.
..........Don't give me that look........ 
If you have the Steampipe update you should be able to mount Portal through the gameinfo.txt, which is the preferable way to do it.
..........Don't give me that look........
*giving you the most evil and scary look possible*
NAhhhhh!
Kidding o.o
I think I seen that page before lol man.....brainfart for the win <_<
Hmm....it'll take some line splicing, but I think I can make the new lines just from the vast number of original lines. :3
Hmm....now to decide if I should edit my voice for Ratman.....
