Need help please on transfering iTunes onto new computer before I go to college in 4 days! Thanks!

I have a problem. The computer that i used for iTunes has died, but now i have a new one that i am attempting to use. I planned to plug in my iPhone and have all the music from my iPhone copy into the library, like my sister did, but it wont work with the new updated iTunes (as seen on the iTunes tab on Apple.com). I am leaving for college in 4 days and i would greatly appreciate if someone could help me out with this before i leave. I have tried everything from trying to find the "hidden files" of my music that are supposedly on my iPhone in "computer", trying using cd's (the problem with cd's is that they copy onto my core library but NOT onto my ipod, and my iPod won't sync to my library unless it erases whats on my iPod, which is don't want it to do). Help would be appreciated! Thanks!