if your host has GD1 not GD2, u wont get any better then this...
ask them or run this script to see what version of GD they have installed.
<?php
phpinfo();
?>
if it's GD version 2, then open
/includes/constants.php find
define('CONVERT_IS_GD2', 0);
change it to
define('CONVERT_IS_GD2', 1);
If it's GD1, then the only sollution is ImageMagick or NetPBM witch is also must be installed by your host.