GET statuses/mentions can be used. That API call returns any mentions of a user, and you can pass the flag include_rts. This will include any retweets of your tweets. If you wanted to list RTs of a specific tweet, you could check the in_reply_to_status_id field in the returned data to see if it matches the original tweet ID.
However even this has a limit (I expect quite higher though) So you will have to do it in a repetitive polling fashion
