You can do the backup to a hard drive. Don't sweat too much over it, everything's going to be fine.
First, you'll want to open up iTunes and hook up the iPad. Look at the left column where your Library, Store, Playlists, etc tab and focus on DEVICES
There will be an icon of an iPad next to whatever the name is. Right-click it and click Transfer Purchases
. This will download everything from the iPad that has been purchased on both iTunes and the App Store and you'll be able to see it under the LIBRARY
If you want to do a backup beforehand, just in case, after you plug it in, click its name, and you'll see a summary of the device and what it contains.
Scroll down, to where it says Backup, and click Back up to this computer, then hit Apply on the bottom right.
It's not going to let you update, although it'll be good just to click Check for Update
just in case something has changed since then (I haven't done this in like two years now it seems
), otherwise you're going to want to click Restore.
This guide is for iOS 5, but it's pretty much the same for 6 too:
If you're not sure, feel free to ask.