you will need to edit the date picker code, and add the yearRange variable:
yearRange: '1970:2025',
for example:
$(function(){
$('#datepicker_1').datepicker({
dateFormat: 'mm/dd/yy',
showAnim: 'show',
changeYear: true,
yearRange: '1970:2025',
onClose: closeDatePicker_datepicker_1
});
});
more details can be found here:
http://api.jqueryui.com/datepicker/#option-yearRange