Your LiveID password can be reset at http://account.live.com If you have set up an alternate email address and secret questions for that LiveID, the process can be fairly simple. If you did not set up an alternate email address or don't know the answer to the secret question, you will need to contact support - via email if your subscription status can't be validated.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
However, I think a much easier solution for you would be to look for a discounted retail copy and simply uninstall your current copy and then install and activate a new subscription with the retail key with a new LiveID. Be sure to record the LiveID and Password used, perhaps on the retail box, in case you need to reinstall later or want to add another PC to the subscription.
Note that when your current subscription expires, you will have a grace period before it stops working completely. It may be as long as 30 days, though I don't know the exact term.
-steve
