Pro costs US$18.88 which covers you for 6 months of updates & email support. If your 6 months are up (sounds like yours certainly are), then you'll have to buy Pro again.

If you bought a version of Pro that promised you a "once only payment" or something similar, it was a scam.
The only place to get any version of LW is www.limewire.com
If you don't want to pay for a new Pro, you can download the latest basic (free) version from this site.