I would go with the Date::Format module eg:

my @date = localtime(time);
#get yesterdays date;
$date[3]--;
$date[6]--;
my $run_date=strftime("%A %e %B %Y", @date);
[download]

Similarly for last months date

my @date = localtime(time);
#get last months date;
$date[4]--;
my $run_date=strftime("%A %e %B %Y", @date);
[download]

This will return something linke

Sunday 27 May 2001

Mess around with the template if you want a different format (The template is the "%A %e %B %Y" bit)

Diarmuid