if you are using a network card, you can alter the mac address of it, and this will give you a new ip. When you do it, only change the last character of the mac address, and make sure you have the modem unplugged at the time. Then leave the CM off for about 1minute, reboot the pc and turn it back on and you will have a new ip.
Alternatively you can set it up on the USB connection, but i wouldn't recommend this. If you are on USB at the moment, switch to ethernet and this will improve your connection and give you a new ip address.
I don't really think that the individual ip address is the problem, unless someone has started a Ddos attack on you. What leads you to believe that this is the case?
MB