Convert strange encoded databe sql file to UTF-8 (Greek Characters included)

gistfile1.php

<?php
// helper function for utf-8
function file_get_contents_utf8($fn) {
$content = file_get_contents($fn);
return mb_convert_encoding($content, 'UTF-8',
mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true));
}
// open corrupted text file
$string = file_get_contents_utf8("input_file.sql");

// substitute
$string = str_replace( "α", "α", $string );
$string = str_replace( "β", "β", $string );
$string = str_replace( "γ", "γ", $string );
$string = str_replace( "δ", "δ", $string );
$string = str_replace( "ε", "ε", $string );
$string = str_replace( "ζ", "ζ", $string );
$string = str_replace( "η", "η", $string );
$string = str_replace( "θ", "θ", $string );
$string = str_replace( "ι", "ι", $string );
$string = str_replace( "κ", "κ", $string );
$string = str_replace( "λ", "λ", $string );
$string = str_replace( "μ", "μ", $string );
$string = str_replace( "ν", "ν", $string );
$string = str_replace( "ξ", "ξ", $string );
$string = str_replace( "ο", "ο", $string );
$string = str_replace( "Ï€", "π", $string );
$string = str_replace( "ρ", "ρ", $string );
$string = str_replace( "σ", "σ", $string );
$string = str_replace( "Ï„", "τ", $string );
$string = str_replace( "Ï…", "υ", $string );
$string = str_replace( "φ", "φ", $string );
$string = str_replace( "χ", "χ", $string );
$string = str_replace( "ψ", "ψ", $string );
$string = str_replace( "ω", "ω", $string );
$string = str_replace( "Ï‚", "ς", $string );

$string = str_replace( "ά", "ά", $string );
$string = str_replace( "ή", "ή", $string );
$string = str_replace( "ί", "ί", $string );
$string = str_replace( "ÏŒ", "ό", $string );
$string = str_replace( "ύ", "ύ", $string );
//$string = str_replace( "Ï?", "ύ", $string );
$string = str_replace( "ÏŽ", "ώ", $string );

$string = str_replace( "Α", "Α", $string );
$string = str_replace( "Ά", "Ά", $string );
$string = str_replace( "Î’", "Β", $string );
$string = str_replace( "Γ", "Γ", $string );
$string = str_replace( "Δ", "Δ", $string );
$string = str_replace( "Ε", "Ε", $string );
$string = str_replace( "Ζ", "Ζ", $string );
$string = str_replace( "Η", "Η", $string );
$string = str_replace( "Θ", "Θ", $string );
$string = str_replace( "Ι", "Ι", $string );
$string = str_replace( "Κ", "Κ", $string );
$string = str_replace( "Λ", "Λ", $string );
$string = str_replace( "Îœ", "Μ", $string );
$string = str_replace( "Ν", "Ν", $string );
$string = str_replace( "Î?", "Ν", $string );
$string = str_replace( "Ξ", "Ξ", $string );
$string = str_replace( "Ο", "Ο", $string );
// p below
$string = str_replace( "Ρ", "Ρ", $string );
$string = str_replace( "Σ", "Σ", $string );
$string = str_replace( "Τ", "Τ", $string );
$string = str_replace( "Î¥", "Υ", $string );
$string = str_replace( "Χ", "Χ", $string );
$string = str_replace( "Φ", "Φ", $string );

$string = str_replace( "Ω", "Ω", $string );

// NEEDS TO BE LAST!
$string = str_replace( "Π", "Π", $string );
$string = str_replace( "έ", "έ", $string );

// print string
echo $string;

// save to new file
file_put_contents( "output_file.sql", $string );
?>