If you have the CTR (Click-to-Run) Office 2013 install, it is supposed to automatically update when you are online. Last week, 3 days after the SP1 release Office had still not updated. I forced Office to check for updates and SP1 was installed.
Go to FILE >> ACCOUNT >> right pane.
Click the UPDATE OPTIONS drop down menu.
Select DISABLE UPDATES and yes to the warning dialog that will pop up.
Then click the UPDATE OPTIONS drop down menu again and select ENABLE UPDATES.
This forces Office to go online and check for new updates.
After clicking Enable within 2 seconds I had an update notice and SP1 was installed!
– Troy @ TLC