According to a leaked roadmap acquired by ZDNet, Office for iOS and Android won't be coming until fall 2014. The roadmap details various different Office products, including "Gemini wave 1.0" that will launch the Metro-style of core Office products. They will be designed with touch in mind and run on Windows 8 and Windows RT. These will be coming by October 2013.
Gemini 1.5 will come in April 2014 and consist of an update to Mac Office, updates for Office for Windows Phone, and support for LSX hardware. Finally, fall 2014 is listed as the time period for when Office for iOS and Android will be released. Previous rumors had suggested iOS and Android versions would be released in early- to mid-2013.