If you're using $Area as the key to your hash

my @sorted_areas = sort { $a <=> $b } keys %NetAreaHash

will sort them in ascending order (swap $a and $b if you prefer descending).

If you're going to follow xdg's advice and have $Area as the value of the hash, use

my @sorted_areas = sort { $NetAreaHash{$a} <=> $NetAreaHash{$b} } keys %NetAreaHash

Again, swap $a and $b for descending.

As to your main problem, I have discovered a truly remarkable solution which this textbox is too small to contain (tm) :-)