You will not get a new disk, nor can you renew your subscription. You will probably get a free 6 month extension, though, and you can verify this by signing in at
https://billing.microsoft.com
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 still desire to install OneCare to 2 more PCs, you need to go to http://onecare.live.com, click Member Accounts on the left, then Add a Computer. You will activate with the subscription LiveID used for the 1st PC.
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~