my website hacked !

Hello,
I have big problem beacuse today on 2013-10-07 my website on joomla 2.5 with Gavick template was hacked, or there is some script that my Server provider bolcked !
My company is stoped and I don't know what to do...
Link to my website http://mad.home.pl/WEB/NOVAVERTA/ or [url]komorylakiernicze.com[/url], the home.pl send me email that on "/WEB/NOVAVERTA/images/banners/mailer.php\" is some problem.

Please help me what to do.... and unblock website.

We need more information to suggest anything such as what was replaced, any messages hackers left behind and so on.

Considering your host suggest mailer.php inside images folder it looks similar to "Hmei7" hacker.

Please see following link if and compare log files with your files and logs.

http://www.joshpate.com/2013/01/how-to- ... -web-site/

Also for future reference make sure all your plugins / components are updated to latest versions and try to use extensions where developers are active with.

See you around...