Should be available via Windows update. Having a low spec laptop was still unavailable to me up to now. Got fed-up so downloaded the full SP1 from here;
http://www.microsoft.com/downloads/d...DisplayLang=en
It's a 434 MB download but you can burn it to disc so in the event of future PC failure you'll have your SP1 ready to install instead of having to download again.
To install I disconnected from the internet and disabled ALL security software including Windows Defender. So if you have a security suit then disable all of it. I also disabled the side-bar.
The program self extracts and it took just under an hour. Re-established everything and connected to the internet and all is well. Looks as I've saved some disk space but will have to verify that.