Here's version of what I use:

Public Sub Main()
Dim sPath As String
Dim oDocCurWeek As Document
sPath = "H:\Weekly Reports\"
Set oDocCurWeek = ActiveDocument
With oDocCurWeek
   .SaveAs FileName:=sPath & "Weekly Status Report " & fReportPeriod
   Set oRng = oDocCurWeek.Bookmarks("ReportPeriod").Range
   oRng.Text = fReportPeriod
   oDocCurWeek.Bookmarks.Add Name:="ReportPeriod", Range:=oRng
End With
End Sub

Public Function fReportPeriod() As String
Dim dFirstDayOfWeek As Date
Dim dCurrDayOfWeek As Date
Dim sReportPeriod As String
dFirstDayOfWeek = DateAdd(Interval:="d", _
   Number:=-(Weekday(Date:=Date, FirstDayOfWeek:=vbMonday) - 1), _
   Date:=Date)
dCurrDayOfWeek = Date
sReportPeriod = Day(Date:=dFirstDayOfWeek) & "-" & Day(Date:=dCurrDayOfWeek)

If fMonthName(dDate:=dFirstDayOfWeek) = _
   fMonthName(dDate:=dCurrDayOfWeek) Then
   fReportPeriod = fMonthName(dDate:=dFirstDayOfWeek) & " " & _
       sReportPeriod
Else
   fReportPeriod = fMonthName(dDate:=dFirstDayOfWeek) & " " _
       & Day(Date:=dFirstDayOfWeek) & "-" & _
       fMonthName(dDate:=dCurrDayOfWeek) & " " _
       & Day(Date:=dCurrDayOfWeek)
End If

End Function

Public Function fMonthName(dDate As Date) As String
fMonthName = MonthName _
   (Month:=DatePart("m", Date:=dDate), _
   Abbreviate:=True)
End Function

HTH,
Dave

You might like to look at Macropod's work on date fields linked from
http://www.gmayor.com/insert_a_date_other_than_today.htm