Installing script in Firefox

Hi,
I have developed a userscript for Firefox users that consists of some
accessibility tools for the browser users.
Since, these are accessibilty tools for the differently abled, I do
not expect them to download Greasemonkey first, then go to my website,
fetch anf install the the script.
TO make this process hassle free, I have developed a small desktop
app, which detect whether Firefox is installed on the user's system.
If Firefox is detected, then give the user an option to install the
script on click of a button.
Done!
But the problem is I don't know how to install this script from
outside the browser.