DOS attack

[Kelly Thomas]

A site on my server seems to be experiencing a denial of service  
attack or some wacked out robot. It has "requested" more than 64,000  
times yesterday from two ip addresses. It's kind of slowing down  
other sites. I already have IP blocker "storms.org" installed but it  
seems to not be working. Also, the attack seems to change IP address  
every day, yet it's confined to networks owned by Sprint. I do not  
have access to my "cable modem router settings" and in the sharing  
pane of OSX System Prefs, the firewall says that there is another  
firewall running and I should disable that one to use the apple FW.  
I'm not aware of such additional firewall software unless it's a part  
of frontier or IP blocker. I'm not an expert but I'm not seeing any  
unusual processes running either. When i quit all applications, I  
still get the FireWall message.

Any Thoughts on how I can battle this?
Thanks!
/kelly