I haven't had a lot of luck with FQL and prefer to use the graph api
Using this in combination with the facebook SDK dll you can quickly retrieve information about a post as a json object using the following code.
var client = new FacebookClient(accessToken);
var jsonPost = (JsonObject) client.Get(postId);
As for seeing who has shared your objects I'm not sure if that can be done using the graphAPI, you would be able to see likes and comments of a object by using
var client = new FacebookClient(accessToken);
var jsonLikes = (JsonObject) client.Get(postId + "/likes");
var jsonComents = (JsonObject) client.Get(postId + "/comments");