Help with Server Time using Recurring Timer Widget

We are using the recurring timer widget for our WordPress website and it works perfectly the way we want it to work. The only problem with it is that the countdown depends on the persons local time. How can I set a server time so that no matter what the local time on someones computer the countdown will end correctly.

**Here is the widget and below is basically his code.
WordPress Recurring Timer Widget WordPress Plugins

var RT_Widget;
    var rt_timers = [];

    function rt_update() {
    	setTimeout('rt_update()', 1000);
    	for ( var i = 0; i < rt_timers.length; i++ ) {
    		rt_timers[i].update();
    	}
    }

    (function($){
    	RT_Widget = function(start, end, start_next, css_class) {

    		this.update = function() {
    			var now = new Date();
    			//alert(now.toLocaleString());

    			if(now >= this.start && now < this.end) {
    				$(this.css_class + ' .rt-countdown').hide();
    				$(this.css_class + ' .rt-until').hide();
    				$(this.css_class + ' .rt-on').show();
    				return;
    			} else if(now > this.end) {
    				this.start = this.start_next;
    			}

    			//there is probably a better way to do this
    			var total = (this.start - now) / 1000; //remove millis
    			var days = parseInt(total / 60 / 60 / 24);
    			total -= days * 60 * 60 * 24; //remove days
    			var hours = parseInt(total / 60 / 60);
    			total -= hours * 60 * 60; //remove hours
    			var minutes = parseInt(total / 60);
    			total -= minutes * 60; //remove minutes
    			var seconds = parseInt(total);

    			$(this.css_class + ' .rt-on').hide();
    			$(this.css_class + ' .rt-days').html(days);
    			$(this.css_class + ' .rt-hours').html(hours);
    			$(this.css_class + ' .rt-minutes').html(minutes);
    			$(this.css_class + ' .rt-seconds').html(seconds);
    			$(this.css_class + ' .rt-countdown').show();
    			$(this.css_class + ' .rt-until').show();
    			$(this.css_class + ' .rt-event').show();
    		};

    		this.get_js_date = function(date_string) {
    			var date_millis = Date.parse(date_string);
    			if(isNaN(date_millis)) {
    				alert('Error parsing ' + date_string);
    			}
    			var date = new Date();
    			date.setTime(date_millis);
    			return date;
    		};

    		//constructor stuff
    		this.start = this.get_js_date( start );
    		this.end = this.get_js_date( end );
    		this.start_next = this.get_js_date( start_next );
    		this.css_class = '#' + css_class;

    	};

    	$(document).ready(function($) {
    		//kick it off, unless there's no widget(s)
    		if( $('.rt-content').length > 0 )
    			rt_update();
    	});

    }(jQuery));