Actually, you should only add the URL as parameter (url encoded) to the sharer.php:
<a href="<?php echo 'http://www.facebook.com/sharer.php?u=' . urlencode(<url to share>); ?>"><img ... /></a>
It automatically takes the Open Graph data from the shared URL, see this page: http://ogp.me/
I assume all the other parameters are deprecated, at least it did not work for me some months ago. The only thing you could try is to encode all data with the PHP function "urlencode" - but i would suggest using the correct way and implement Open Graph correctly. That way you can even just take the URL, put it on Facebook manually and it will take the correct data.
If the content is completely dynamic, you should consider using Open Graph Actions: https://developers.facebook.com/docs/opengraph/
Or if that is too complicated, use the FB.ui feed dialog:
https://developers.facebook.com/docs/reference/dialogs/feed/
...but don´t forget to include the JavaScript SDK: