"How can she keep the music she has on her ipod and then start with new music once she gets a computer?"
She needs to change the update preference in the iPod Summary tab to "Manually manage music and videos" and click Apply. That way she can connect to an empty iTunes with the risk of accidentally erasing the iPod.
Using iPod with Multiple computers
Managing content manually on iPod
Once she has a new computer she can retrieve the songs from the iPod. If she has any iTMS purchases, the transfer of purchased content from the iPod to authorised computers has been introduced with iTunes 7. A paragraph on it has been added to this article:
Transfer iTunes Store purchases using iPod
The transfer of non iTMS content such as songs imported from CD is designed by default to be one way from iTunes to iPod. However there is a manual method of accessing the iPod's hard drive and copying songs back to iTunes on Windows posted in this thread:
MacMuse - iPod to iTunes
If you prefer something more automated then there are a number of third party utilities that you can use to retrieve the music files and playlists from your iPod, this is just a selection. Have a look at the web pages and documentation for these, they are generally quite straightforward. You can read reviews of some of them here:
Wired News - Rescue Your Stranded Tunes
YamiPod Mac and Windows Versions
iGadget Windows Only
iPod Access Mac and Windows Versions
PodUtil Mac and Windows Versions
iPodCopy Mac and Windows Versions
PodPlayer Windows Only
CopyPod Windows Only
Whichever of these retrieval methods she chooses, she should keep the iPod in manual mode until she has reloaded iTunes and is happy with the playlists etc then it will be safe to return it auto-sync again
