My site has been hacked

Hi guys,

I have problem. My site has been hacked properly.

They are using my site to send SPAM.

List of files that been attacked:

5504 /xmlrpc.php
2920 /wp-content/themes/twentythirteen/css/object.php
17 /wp-login.php
8 /wp-content/themes/twentythirteen/inc/xml44.php
7 /wp-content/themes/twentyfifteen/js/inc.php
6 /wp-includes/Text/Diff/Renderer/diff.php
6 /wp-content/themes/twentyfifteen/image.php
5 /wp-content/themes/twentythirteen/taxonomy-post_format.php
5 /wp-content/plugins/wp-db-backup-made/info11.php
4 /wp-content/themes/enfold/help.php
4 /wp-admin/media-upload.php
2 /wp-includes/Text/Diff/Engine/native.php
2 /wp-includes/pomo/entry.php
2 /wp-includes/js/tinymce/themes/alias.php
2 /wp-content/themes/enfold/framework/js/config.php
2 /wp-content/themes/enfold/config-layerslider/LayerSlider/static/js/minic olors/diff.php
2 /wp-content/themes/enfold/config-events-calendar/views/pro/admin.php
2 /wp-admin/theme-editor.php
1 /wp-content/themes/enfold/404.php
1 /default.php

Can you help me find a solution?