Upgrading to iOS 5 on new computer

The last time I synced my iPod Touch (4G) was on a now-broken MacBook Pro (dead logic board), and when I'm trying to upgrade it to iOS 5 on my replacement laptop it's telling me that it'll erase all of the content on it unless I do the upgrade on the computer that I normally sync with (which isn't possible). I have a Time Machine backup of my old laptop, but for some reason it doesn't have the iTunes library xml file, so I can't convince it that it's the same computer. Am I stuck wiping and restoring everything, or is there some other way to go about this upgrade that will preserve the contents of my iPod?

 

The main issue I have is losing all of the data for my applications. Am I correct in assuming that all of that (game progress, application settings, etc) will be gone after this? If it retains the application data, then it's more or less a non-issue since I have other copies of everything.

 

Its phone support period is long gone (~11 months old with no AppleCare), so would they actually bother helping me or just tell me that I'd need to buy AppleCare in order to get support?

I'd have expected Apple to better account for a situation in which someone's computer unexpectedly dies. :s

 

No. It was an aftermarket SSD, so I took it out, wiped it, and put it in my new laptop.