Update your old iPads backup followed by a sync with iTunes.
The first time you connect your new iPad to iTunes, you will be prompted to transfer the backup for your old iPad to yor new iPad which will be followed by a sync.
Continue to backup the old iPad until the new one arrives. You should back up and sync with iTunes as well. Syncing with iTunes will transfer all of your purchased content into iTunes on your computer.
When the new iPad arrives - you can plug in into your computer, launch iTunes and iTunes will ask if you want to restore from the iPad backup or set up as new. Restore from the iPad backup and then sync with iTunes to move all of your iTunes content onto the new iPad.
If you want to restore from an iCloud backup - read this.
I think that you will have to download all of your purchased content again but you still have to sync movies (if you don't live in the US) and photos from iTunes. It is easier - IMO - to just use iTunes rather than restoring from iCloud - but you can be the judge of that yourself.
This explains the process as well.
Sync your old iPad with iTunes and transfer all photos, etc. to your computer. Then you can sync your new iPad to the same iTunes.
You could also make a backup in iTunes of the old one and when setting up the new one restore it from the backup.
Copy you purchases off your old iPad to your computer's iTunes via File > Transfer Purchases. You can then backup your current iPad and restore the new iPad from that backup (a list of what is included in a backup is in this article - it excludes music, videos, synced photos).
As the backup doesn't contain the actual apps, just their settings and content, for the restore to work completely you'll need all the relevant apps in your computer's iTunes library - otherwise the restore won't be able to install the apps and therefore their content (File > Transfer Purchases should copy them over from your old iPad, otherwise you can re-download them for free).
The restore won't copy passwords onto a different device, so you will need to re-enter your email, router, and any website passwords onto the new iPad
If you have backed up your old iPad to your computer and are planning to do the same, the first time you sync your iPad it will ask you if you want to restore your new iPad from a backup or start fresh. If you select to restore from a backup,
It will have an option to select the name you named your old iPad when you set it up. Select that option and it will start transferring information.
I have same dilemma only I'm on vacation and don't have my computer with me. Should I register under new user until I can sync it back to my old account, or do I have to wait until my vacation (6 weeks) is over to transfer all of my books and aps?
Sign into iTunes Store for your country using your current ID. You can re-download all (or only the essential ones) purchases again for free.
Also, if you setup iCloud you can restore from the iCloud backup.