var MonthName = new Array(12)
MonthName[0] = "stycznia "
MonthName[1] = "lutego "
MonthName[2] = "marca "
MonthName[3] = "kwietnia "
MonthName[4] = "maja "
MonthName[5] = "czerwca "
MonthName[6] = "lipca "
MonthName[7] = "sierpnia "
MonthName[8] = "września "
MonthName[9] = "października "
MonthName[10] = "listopada "
MonthName[11] = "grudnia "

function getDateStr(){
var Today = new Date()
var Day = Today.getDate()
var WeekDay = Today.getDay()-1
var Month = Today.getMonth()
var Year = Today.getFullYear()
var LastMonday = Day - WeekDay

if (LastMonday<1) LastMonday=1;

return  LastMonday + " " + MonthName[Month] + " " + Year
}