You have been scammed. Basic LW is free, Pro costs US$18.88 for 6 months of email support & upgrades. Read this, it'll make things clearer:
http://www.gnutellaforums.com/showth...threadid=28751

Only get LW from the official site: www.limewire.com

Contact your CC company & try to get your money back. Even though you paid a while ago, you've only just become aware of the fraud. They might be able to help you out