Command to 'overwrite' existing sheet

Hi all,

I have a macro I am running to pull reports from 2 different sheets and pasting to a new sheet:

Sub STAT2011()

Worksheets.Add().Name = "STAT-2011"
Sheets("Nov 2011").Activate
    Sheets("Nov 2011").Columns("A:B").Copy Destination:=Sheets("STAT-2011").Columns("A:B")

Sheets("Nov 2011").Columns("G").Copy Destination:=Sheets("STAT-2011").Columns("C")
    Sheets("STAT-2011").Columns("C").Value = Sheets("Nov 2011").Columns("G").Value

Sheets("Dec 2011").Columns("G").Copy Destination:=Sheets("STAT-2011").Columns("D")
    Sheets("STAT-2011").Columns("D").Value = Sheets("Dec 2011").Columns("G").Value
    Sheets("Annual 2011").Columns("G").Copy Destination:=Sheets("STAT-2011").Columns("E")
    Sheets("STAT-2011").Columns("E").Value = Sheets("Annual 2011").Columns("G").Value


Sheets("STAT-2011").Activate
End Sub

What I want to include is a command at the beginning of the code so that even though there is already a sheet called "STAT-2011" (created the month prior) the macro will 'overwrite' that sheet and create the new one?....

TIA