im not sure if this is what you really want
to get the value of the current date on this format 00-00-0000 try this
$currentDate = date('m-d-Y');
you can either make use of substr to break it or just assign individual variable on each date function like this
$currentDay = date('d');
$currentMonth = date('m');
$currentYEar = date('Y');
and to select the current value from your drop down either u have to assign each value on a array to check the current date is equal to the value from array or just test it 1 by 1