Q: Unable to upload newest version iOS

I would be careful about how you go about updating, in order to avoid many of the problems others have had. For one thing, I would not do an install on top of your old system, but rather do a "clean system install" in order to get rid of your corrupted and garbage files in your old system. They can cause you problems and make your life on your iPad miserable.

The first thing you should do is have your backups completed. It's preferable to have your backups done on your iTunes program on your computer, as that's the most complete. Be sure you understand what won't be backed up, so you can save them another way. Read the Apple Support documents on it.

Then after that, use your iTunes program to reset your device to its factory default state, as a clean and fresh iPad, as if it came right out of the factory doors. Then you can restore your data from the backup you have on iTunes. The following are the Apple Support documents on what I just said.

Choosing an iOS Backup Method (Should I Use iTunes or iCloud to back up ...)

https://support.apple.com/kb/HT5262

Back up and Restore your iOS Device with iCloud or iTunes

http://support.apple.com/kb/ht1766

iTunes: About iOS Backups

http://support.apple.com/kb/ht4946

Create and Delete iPhone, iPad and iPod Touch Backups in iTunes

http://support.apple.com/kb/ht4946

iOS: Troubleshooting Encrypted Backups

http://support.apple.com/kb/TS5162

Use iTunes to Restore your iOS Device to Factory Settings

http://support.apple.com/kb/ht1414