jqGrid PHP filter by date - today & today +30 days?

Question

I am using JqGrid PHP.

This works--- BUT how would I substitute Today for the first "02/10/2012" and today +30 days for the second date?

$arr = <<< FILTERDATE
   {
      "groupOp":"AND",
      "rules":[
      {"field":"ExpDate","op":"ge","data": "02/10/2012"},
      {"field":"ExpDate","op":"le","data": "03/10/2012"}
      ]
   }
FILTERDATE;

$grid->setGridOptions(array(
   "caption"=>"NATDA Members Expiring in the Next 30 Days", 
   "rownumbers"=>true, 
   "rownumWidth"=>35,
   "sortname"=>"ExpDate",
   "autowidth"=> true,
   "multiselect"=>true,
   "hoverrows"=>true, 
   "scroll"=>1,
   "search"=>true,
   "postData"=>array( "filters"=> $arr )
));