I carried on searching and have now found that you can add google fonts to MS Word and thought it worth mentioning for the benefit of Mac users who use Office 2008 for mac, that once you have downloaded your chosen google font when you install it, it lands on the Font Book. When I tried it, it didn't appear in the Word library of fonts, but if you go to the Font book and copy it from the User list of fonts to the Windows office compatible section, it then gets installed in the Word fonts library.

Hope this helps someone ?