iPhone Locked With Passcode and iTunes Problem

I entered the wrong passcode on my iPhone 5C too many times so now my iPhone says, "iPhone is disabled, please connect to iTunes."

I want to sync my iPhone to iTunes so I can backup my data and then restore my iPhone. I connected my iPhone to my computer (which I have synced to before) and I get a pop-up that reads, "To allow access, please respond on your iPhone."

I also have used iCloud to backup my iPhone in the past. I set the backup to automatic.

How do I find out how recent my iCloud backup is?

What can I do to allow access to my iPhone through my computer?

Thanks