Jquery plugin - how to access variables through public functions

Hello, I am learning how to create a jQuery plugin but I am having trouble with some parts, the plugin scrolls through the content in a container either left to right, bottom to top, and viceversa and it works fine however I now want to extend it’s functionality so I can stop and restart the scrolling and that is where I am having trouble, I currently have this


;(function($){
	$.fn.tlakScroller = function(o) {
		return this.each(function() {
			var c = $(this);
			o = $.extend( {}, $.fn.tlakScroller.defaultOptions, o );
			op = '-';
			ph = c.parent().height();
			pw = c.parent().width();
			switch ( o.dir ) {
				case 'top':
					o.l = ph - c.height();
				break;
				case 'bottom':
					o.l = ph - c.height();
				break;
				case 'left':
					o.l = pw - c.width();
				break;
				case 'right':
					o.l = pw - c.width();
				break;
				default:
					o.l = ph - c.height();				
				break;
			}
			object = setInterval(function(){
				if ( o.startpixels == o.l || o.startpixels >= 1 ) {
					op = setCount(op);
				};
				if ( op == '-' ) {
					o.startpixels --;
				} else {
					o.startpixels ++;
				};
				c.attr('style', 'position: absolute;' + o.dir + ':' + o.startpixels + ';');
			}, o.speed);
			c.on('mouseover', function(){
				clearInterval(object);
			});
			c.on('mouseout', function(){
				object = setInterval(function(){
				if ( o.startpixels == o.l || o.startpixels >= 1 ) {
					op = setCount(op);
				};
				if ( op == '-' ) {
					o.startpixels --;
				} else {
					o.startpixels ++;
				};
				c.attr('style', 'position: absolute;' + o.dir + ':' + o.startpixels + ';');
			}, o.speed);
			});
		});
		function setCount(d) {
			switch ( d ) {
				case '+':
					d = '-';
				break;
				case '-':
					d = '+';
				break;
			}
			return d;
		};
	}
	$.fn.tlakScroller.defaultOptions = {
		dir: 'top',
		scrollback : true,
		speed: 100,
		startpixels: 0
    }
})(jQuery);

What I want to do is create a function that calls clearinterval and another one for setinterval on the target element, I tried creating functions but I always get undefined function in firebug, can someone give me an example on how I could create a public function to access and modify the variables of the object