Finally the administrator admit that they have a security loop hole in there server, they solve the problem temporally, but I think they still can't find a concrete solution for it. I am not sure what kind of an attack is this, but I am sure I am not alone in this issue.
There seems to be another hijack on my site, now is a company called antivirusonlinescanner.com, somehow they manage to route all my Google, MSN, Yahoo traffic to their site.
Base on a friend of mine who work in IT security field, the hijacker inject a worm in the DNS or ISP servers, that way all traffic coming from major search engine will be routed to their site.
I am not sure where is the weakest link, because the packet need to be routed to several servers before it hit my web server, hopefully my web hosting company can help me resolve this issue, because if not, my site rating will definitely go down exponentially.