I run Sibelius on a Macbook Pro with no problems at all; having said that, there are much cheaper ways of achieving what you want to do.
My suggestion is to use Muse Score, which is a free programme, available here
http://musescore.org/
If you write your musical examples on Muse Score then take a screen shot of the relevant passage using Grab (which you'll find in the Utilities folder in your Applications folder on your Mac), you can then drag and drop the screen shot into the word processor of your choice. I use Open Office for all my word processing as opposed to Microsoft Word, because they are virtually identical in their functions and Open Office is free (and available here
Download OpenOffice.orgAqua for Mac OSX )