How to use Hidden title numeric sorting for thousands separator

Hi there, im using dataTables with "Hidden title numeric sorting" plugin because my table rows look like this:

1,100.30
8,000.10
120.50

using "," as thousand separators. But im getting the rows sorted like:

1,100.30
120.50
8,000.10

What i've added is this as javascript:

jQuery.extend( jQuery.fn.dataTableExt.oSort, {
    "title-numeric-pre": function ( a ) {
        var x = a.match(/title="*(-?[0-9\.]+)/)[1];
        return parseFloat( x );
    },
 
    "title-numeric-asc": function ( a, b ) {
        return ((a < b) ? -1 : ((a > b) ? 1 : 0));
    },
 
    "title-numeric-desc": function ( a, b ) {
        return ((a < b) ? 1 : ((a > b) ? -1 : 0));
    }
} );

	oTable = $('#reprtable').dataTable({
		"bJQueryUI": true,
		"sPaginationType": "full_numbers",
		"sDom": '<""f>t<"F"lp>',
            "aoColumns": [
                null,
                null,
                { "sType": "title-numeric" },
                null
            ]
	});

and my html is:

<td>1</td>
<td>2</td>
<td><span title="1100.30">1,100.30</span></td>
<td>4</td>


Can someone help me please?