You will probably get a free 6 month extension as renewals and new purchases are no longer allowed.
See this post for End of Life information for Windows Live OneCare - http://social.microsoft.com/Forums/en-US/onecaregeneral/thread/81996436-edad-41ba-bdfc-02fc094e2ca9
If you don't see your subscription at https://billing.microsoft.com, you may be using the wrong LiveID. Open OneCare and click Help/About to see the subscription LiveID to sign in with. Also, you may have two accounts under the LiveID, so check if there is a drop-down for the account number when your sign into the Billing site.
You don't need to cancel, but if you wish to do so or confirm the above, you can contact customer service/support.
How to reach support (FAQ) - http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~