What iOS version do you currently have on your iPad 2?
I had 5.0.1 on my iPhone and went into settings, then General, then software update. It said that there was an update for me. Knowing that it might be a lot smaller of a download I went for it this way. The total download was 171mb. I did this connected to wifi.
Perhaps your iOS version is new enough to get the update this way.
I think I did remember to back up my iPhone after that update. Otherwise it would not be on my computer if there was a need for a reinstall.
BTW, my British (girl)friend said wifi like wiffy. I thought it to be so cute that I have adopted it in her honor.
Sent from my iPad using iPF - Peace