jquery change div text

'<div id="'+div_id+'" class="widget" style="height:60px;width:110px">\n\
            <div class="widget-head ui-widget-header" style="cursor:move;height:20px;width:130px">'+
         '<span id="'+span_id+'" style="float:right; cursor:pointer" class="dialog_link ui-icon ui-icon-newwin ui-icon-pencil"></span>'  +
          dialog_title+'</div></div>

I have a div constructed using the above string. After some processing..I have to change the dialog_title in the above div. I am trying to do it with the following code

$('#'+div_id+' .widget-head').text("new dialog title");

While this changes the dialog title..it removes the span element which is used to open a dialog box.

I tried to the replaceWith method with a string with new dialog title..but that shows NaN for title and the span though visible cant be clicked(are events disabled?)

How do I change the text without losing the span and ability to click it.