Are you sure your logic is working? Also where does the get parameters come from (obviously the URL but how are they set there)?
Your date functions, shouldn’t they be set like the value saved in the database
date(Ymd); /Gives YYYMMDD
Also try setting the type value to DATE in the query.. (read the text here:http://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters)
