Need help restoring iPad 2 after disable. I can't restore using computer I synced with as per Apple instructions.

I had to repair my iPad 2 and haven't used it for 3 months. Apparently l set up a passcode before I shut it down prior to the repair and I don't remember it. After numerous attempts of entering the wrong passcode, it is disabled for 60 minutes. I tried to restore it as instructed by Apple but when I connect to iTunes on computer, it won't sync and asks me for my passcode. This is when connected to the only computer I have ever synced with. I don't want to do a restore and erase everything if I can help it. There has to be a better way than losing everything. Apple needs to address this in future iOS updates for mobile devices like send to a secure email or answer security questions.

These are the instructions I am using:

Restore using iTunes

If you've synced your device with iTunes, you can restore your device.

1. Connect your device to the computer you synced with.
2. Open iTunes. If asked for a passcode, try another computer you've synced with, or use recovery mode.
3. Wait for iTunes to sync your device and make a backup. If it doesn't, learn what to do.
4. Once the sync and backup have finished, click Restore [your device].
   
5. When you reach the Set Up screen while restoring your iOS device, tap Restore from iTunes backup.
6. Select your device in iTunes. Look at the date and size of each backup and pick the most relevant one.