This may not apply to anyone else, but I was having the same problem with the update stopping at 3% when I was trying to update it from my wireless laptop (I had the same problem from my connected desktop computer too). For some reason though, when I switched to my next door neighbor's wireless network it updates fine, even though I talked to my neighbor about this and they have the same internet provider and same brand router (he has no problem with me using his wireless when needed).

So if you're going thru a wireless network and have an option of trying another one, I'd definitely suggest that.