upload_max_filesize and post_max_size are php.ini directives of PHP_INI_PERDIR mode which can only be set in php.ini, .htaccess, httpd.conf.
Try create a .htaccess in your web folder with the following entries:
php_value upload_max_filesize 1024M
php_value post_max_size 1024M
then, launch a php page with the following code to check the changed settings:
echo ini_get('upload_max_filesize');