ipconfig /all will show you the IP address. Is this a home machine?
What is it infected with – what does your anti-virus software report? It should also be able to clean the infection.
I would certainly think about changing passwords
I would install Active Ports to review active connections and will show what programs have initialized it. Also install K9 Web Protection from Bluecoat. This would restrict where you computer attempts to go to. Within the Gui (Web Browser), you can see where it’s trying to cnnect to as well. Once you have an antivirus on the computer like AVG Free as well as the following tools:
Good idea to change your passwords. You may want to contact your credit card company to inform them of the situation. They may issue new cards.