use DateTime::Precise;
use strict;
my $t1 = DateTime::Precise->new;

my %months = (
  1  => q{January},
  2  => q{February},
  3  => q{March},
  4  => q{April},
  5  => q{May},
  6  => q{June},
  7  => q{July},
  8  => q{Auguest},
  9  => q{Septemper},
  10  => q{October},
  11 => q{November},
  12 => q{December},
  );
my $thisMonth = $months{$t1->month};
my $prevMonth = $months{$t1->inc_month(-1)->month};
my $t1 = DateTime::Precise->new;
my $monthB4rLast = $months{$t1->inc_month(-2)->month};
my $t1 = DateTime::Precise->new;
my $monthB4rLast1 = $months{$t1->inc_month(-3)->month};

print "This Month is $thisMonth\n";
print "Previous Month is $prevMonth\n";
print "Month before last is $monthB4rLast\n";
print "Month before 2 months is $monthB4rLast1\n";

Output:
-------
ThisMonth is March

Next Month is February
Month before last is January
Month before 2 months is December