Rene,
You just re-subscribe again like it's new. There's a discount automatically applied at checkout for renewals while a subscription is still active.
I see you actually just re-subscribed. Your price was $90 vs the normal $100 (for a 1 year subscription). Your subscription was set to expire on February 21st of this year, and now your new subscription will expire next year on the 21st as well.
Hope that helps, but if you have any other questions, just let me know.
Thanks,
Alex