Get the service pack from Microsoft here
, but choose the "Network Installation" rather than the "Express Installation". You will have to download everything in the service pack, even if you don't need it, but then you will be able to burn it and use it again and again, even on different computers, without having to download anything again.
Get the hotfixes and security updates from here
rather than through Windows Update, and again you will be able to store them and burn them to use over and over on different computers rather than having to run Windows Update and download them again every time you need them.