replace the one at the top:
with the newer one:
and delete the reference at line 298
you can also remove the extra closing script tag.
in the date picker settings, you can select the date format you wish to use, you will then need to add code to reformat the date when it is submitted:
for example, assuming the name of the datepicker element is set to DatePicker:
$_POST['DatePicker'] = date("Y-m-d", strtotime($_POST['DatePicker']));
for the time field, I Would use a select list, format the options in 24 hour time, so have a selection for 10:30 and another 22:30, etc.