I repaired this in php:
/* Draw calendar */
$miesiac = date('n');
$miesiac_pl = array(1 => 'Styczeń', 'Luty', 'Marzec', 'Kwiecień', 'Maj', 'Czerwiec', 'Lipiec', 'Sierpień', 'Wrzesień', 'Pa?dziernik', 'Listopad', 'Grudzień');
$rok = date('Y');
Here, script is checking current date in number format and changing it to name of month in your language. Last one is checking year. After that you have to change code for viewing current date and its done ??
$cal_output .= "
<div id=\"event-list-mini-cal-container\">
<h2 id=\"event-list-mini-cal-month\"><span id=\"event-list-mini-cal-prev\"><a href=\"?month=".date('Y-m', strtotime('-1 month', $calendar_month))."\">«</a> </span><span id=\"event-list-mini-cal-date\">".$miesiac_pl[$miesiac]." ".$rok."</span> <span id=\"event-list-mini-cal-next\"><a href=\"?month=".date('Y-m', strtotime('+1 month', $calendar_month))."\">»</a></span></h2>
<div id=\"event-list-mini-cal\">