use DateTime::Duration ();
my $one_year_from_now = $now->add( years=>1 );

if ($reservation_date > $one_year_from_now) {
do something
}

and then

use DateTime::Duration ();
my $one_week_from_now = $now->add( weeks=>1 );

if ($reservation_date > $one_week_from_now) {
do something
}