You can set Sass up, so that it watches files for you and compiles them on the fly.
sass --watch styles.scss:styles.css
Here's a very good tutorial on getting up and running on a Windows box.
Pay particular attention to point 4.
Oh and BTW, using Github on Windows is not as hard as it sounds.
If you look at the button that says "Clone in Windows", there is a button marked "Zip", which will let you download the repo as a zip file