i-pod to i-tunes to retrieve/match lost downloads

I backed up my computer to an external hard drive, but when my hard drive crashed I couldn't retrieve my downloaded music (in i-tunes). I now only have my purchased tunes in i-tunes and match. I got the music from my i-pod into i-tunes, but they will not play unless the ipod is plugged into the computer, and they won't Match. This ipod is on it's last leg (nano 2, center button doesn't work) and I have a new ipod, but don't want to lose my downloaded music (or have to rip CDs again!)