Customize facebook share button (on quiz result page)

I need to customize the profile result page for a better facebook sharing button. I have a test, with 10 questions. Fore every reply it stores value into a mysql database, and the final page "[login to view URL]" show a custom profile (a custom description + a custom pic), like "if points > 10 then result is profile A", etc. The form is placed into a wordpress page. The result page "[login to view URL]" is on a php page (not under wordpress). Example: the test is under worpress page mysite/articles/which-diet-is-for-you/ . The result is under non-wordpress folder mysite/folder-for-script/diet-archive/[login to view URL] It works fine, but the "share on facebook" need to be optimized: now if the user click on facebook share link it post on facebook wall only a standard pic + standard description of the test. I'd like it will be automatic filled with the custom profile result (custom pic + custom description). In the attached you could find the actual page and a 3rd part website with a good example of what I'm looking for. Feel free to ask further details, thanks.