I am sharing title, image and description of post in Facebook using following code
<a name="fb_share" type="button_count" href="http://www.facebook.com/sharer.php">Share</a><script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share" type="text/javascript"></script>
Once i share post or link to Facebook then it will take title and description.
But when I share the same post or link to Facebook with other title and image, the title and image do not change.
You can pass your url by passing any auto generated value,
Hope this will work for you.