VBA for saving worksheet with dynamic date

VBA for saving worksheet with dynamic date

I want to save an excel workbook at the end of the macro with a dynamic
date in the file name. I want the name to contain the previous month. For
instance, if the macro is run on 8/9/2013 I want the file to save with
7/2013 specified. This is what I have and it works great if I use the
current month. But, if I ran this on 8/9/2013 I would want the file to
save as "Monthly Report 2013-07".
ActiveWorkbook.SaveAs "\\FULL PATH\Monthly Report " & Format(Date,
"yyyy-mm") & ".xls"
End Sub
I've also used something like this previously, but couldn't get this to
subtract a month either:
wbNam = "Monthly Report_"
dt = Format(CStr(Now), "yyyy_mm")
ActiveWorkbook.SaveAs Filename:= wbNam & dt
End Sub
Thanks!