tangor - 4:01 pm on Oct 18, 2010 (gmt 0)

I have no quick answers as I do not know how your site is hosted or whether you have access to the tools or not, however, an interesting article by Steve Gibson [crime-research.org...] (PDF) documents some of the difficulties in dealing with this (dated 2001... things have changed since then). Posted for info on the nature of DDoS attacks only.