Zone alarm is a free software firewall with which you can control which programs access the internet. Download, install set it to block the trojan from accessing the net.
That will keep your computer safe (unless a hacker has already put in backdoor) until you can get rid of it.
Then your best bet is norton.com (my personal fav.) or http://vil.nai.com/vil/default.asp
(mcAfee) and look for a repair file.