my $base_dir = "c:/data/";
my $new_dir  = "d:/new/";

opendir (DIR, $base_dir)
|| die "Could not open data directory\n";
my ($top_file) = reverse sort readdir(DIR);
closedir (DIR);

##</code><code>##

my ($top_file) = reverse sort { ($a=~/\$(\d+)$/)<=>($b=~/\$(\d+)$/) } readdir(DIR);

##</code><code>##

use File::Copy;

move($base_dir.$top_file, $new_dir.$top_file);