I finally found who is the responsible or at least the IP address of the author of this DoS (if generating 1.5Tb of traffic in 2 days and making the monthly traffic exceed thus making the website down is not a DoS, then what is it?) and you can be sure that this guy will have to pay the traffic, sooner or later.
Administrative stuff is taking too long so I think it will be easier to pay the bill now to have the website back up.
Aircrack-ng cost me around 60 euro per month (+ domain names that have to be renewed each year, wireless cards, traffic, ...) and although we have around 30K unique visitors each day, unfortunatly donations are quite low (the total for last year was around 80 euro). The reason why I'm writing this post is to ask for donations to pay that bill (around 130 euro).
So, any donation to firstname.lastname@example.org (paypal) is really welcome.