Auto ip block server 2008

I host game servers on a dedicated machine. The servers have been targeted by a resource ddos maxing out the CPU core the server is on. I stop the attack by blocking the ip. I have to do this manually and I'm not always online to do it. The attacks come in on a specific line in a text file log. Will need to be able to read a text file and filter out everything but the IP address on the line with the attack info. Then import into windows server 2008 firewall to block and possibly check for duplicates .