If you installed iTunes from an old physical "disc," you should go here and download the latest version of iTunes instead.
Any version of iTunes that comes on a disc would be very old, and may not work properly with WIndows 7.
For your actual question, iTunes syncing is generally in one direction, from your iTunes library to the iPod. You cannot use iTunes to transfer song files from iPod to computer (except for songs purchased from the iTunes Store). However, there are third-party methods and utilities that can transfer from iPod to computer. If you do an Internet search on something like "ipod transfer," you should get some links. (The CNET article seems to be popular.)
Once the song files are on you computer's drive, you can add them to your new iTunes library.