Where did you get the music? For example, if you bought it from iTunes, you just redownload it from Apple's servers. If you got it elsewhere, in MP3 format, then you put it on your iPad he same way you put it on your iPod, via iTunes.
In my case, I have at least 200 CDs, so I ripped all of them to my PC. I then use iTunes to sync the music I want to the device of my choosing. I have bought a few albums from iTunes, and I download them to my PC and incorprate the MP3 into my media library. But for those albums, I can just open my iPad and go to the Music app. In there I can go the store and then to the "purchased" section and see all the stuff I bought. I can download anything to any iDevice when I want. However, I have some stuff from Amazon, too, so I can either use the Amazon Cloud Player to play that music over wifi from my iPad or I can download the MP3s and incorporate them into my iTunes music library. Then I can sync songs to my iDevice.
Now, if for some reason you only have music on your iPod, and no copies anywhere else, and it didn't come from iTunes, Amazon, or some MP3 store, then you are going to need to find a way to get it off the iPod, and I'm not sure how to do that as I quit using iPods for music. One should never have your music just on an iPod or iPhone or any iDevices, if you can't get to from your PC or some cloud source. A lot of people seem to manage to get into this situation where all their music is on a device rather than on a PC/MAC and then they face this issue of trying to get it off the device. For Android tablets, this is easy to do, for iDevices, its more complicated.
I do recall seeing of a PC program (other than iTunes) that could read and transfer music from an iPod , but I don't remember the details. You might google around for something like that if no one else can provide the details.
