1. Backing up your third party apps can be just having them accessible to install from your Desktop Manager again, save OTA links etc. to find them. You don't want to do the upgrade, end up wiping your phone through some freak accident and then try to remember what software you downloaded/paid for etc.
2. Since you are upgrading to 4.5 (assuming you have downloaded a 4.5 OS), use the 4.5 DM from BlackBerry's website.
3. As far as service books go, you can send them from your BlackBerry Internet Service page. If you don't know it, go to google, and search "provider blackberry internet service", where provider is of course, your phone carrier. The login will be what u either set up for your e-mail when you got it, or your account credentials to access your provider's account management console. Once you do log in, just click "Service Books" on the left and side. On the next page, just click send service books and you're good to go!
"He that hath no sword, let him sell his garment and buy one."
Jesus, Luke 22:36
"The deadliest weapon in the world is a Marine and his rifle."
Gen. John Pershing, U.S. Army