Uhm, what you're asking seems strange to me... if you need to inputs of dates why do you want to use only one input?

Anyway, once the first date is selected you can store it in a var and clear the input to get the second date:

        var firstDate = false,
        $( "#from" ).datepicker({
         minDate: -2,
          maxDate: "+1d",
          changeMonth: true,
          numberOfMonths: 2,
          onClose: function( selectedDate ) {
              if ( firstDate === false ) { // if first selection
                  firstDate = selectedDate; // store the first date
                  $("#from").val('').datepicker( "option", "minDate", selectedDate);  // set the min date of it self
              // if second date...
              else {
                  secondDate = selectedDate; //

I don't recommend, but it should work.