Hacked by 1923 Turk – Help!..?

I have been hacked (defaced)by the 1923 Turk grup and am looking for some help? I have taken the site off-line (it has only been live for 2 months!) and just started to achieve some decent rankings.

As far as I am aware, having what advice I could follow online they have managed to deny me permission /access to my config.php file which is where they have infiltrated my files?

I’m not a developer, coder, so really do not know what I am doing here, can anyone please advise what to do? maybe lead me in the direction of a reputable resource who might be able to fix this quickly for me?

All help appreciated!

Thanks