I just need to search and replace '()' with '{}' and '=' with '=>'.

Instead of replacing
( ... )
with
{ ... }
replace it with
new_ordered_hash( ... )
and define new_ordered_hash as follows:

sub new_ordered_hash {
   my %ordered_hash;
   tie %ordered_hash, 'Tie::IxHash';
   %ordered_hash = @_;
   return \%ordered_hash;
}
[download]

Untested.

Don't forget to untie the lower level hashes when appropriate.

Note: This falls under "2) parsing the file yourself", from my previous post.