if the one in your sig is yours then track each traffic buy like...
http://www.ipartychat.com/?AFNO=1-1 (Broker 1)
http://www.ipartychat.com/?AFNO=1-2 (Broker 2)
http://www.ipartychat.com/?AFNO=1-3 (Broker 3)
just keep increasing the number after "-" as all sign ups/sales will then seperate in stats