Website hacked

[ Moderator note: moved to Fixing WordPress. ]

Hi,

I have big problem with my website(url: zupa-bezgresnog-zaceca-bdm.hr) which seems to be crashed. Every time I open my website or admin interface it just downloaded some php file with this content:
<?php
/**
* Front to the WordPress application. This file doesn’t do anything, but loads
* wp-blog-header.php which does and tells WordPress to load the theme.
*
* @package WordPress
*/

/**
* Tells WordPress to load the WordPress theme and output it.
*
* @var bool
*/
define(‘WP_USE_THEMES’, true);

/** Loads the WordPress Environment and Template */
require( dirname( __FILE__ ) . ‘/wp-blog-header.php’ );

I also tried to sign in with cpanel or filezilla but my access was suddenly denied. In my opinion it is some malware and I don’t have experience with it so can you help me solve this problem ?

Thank you a lot,
Filip