Norton Internet Secuirty 2009 expiring

I have Norton Internet Security 2009 installed on 3 computers.  It is set to expire in 3 days.  I bought another 3-user Norton Internet Security 2009 about 6 months ago?

 

What do I need to do to upgrade this?

 

Is it possible to upgrade to Norton Internet Security 2010 for my 3 computers and use the license in the 3 user 2009 box?  If so, how?

 

If I upgrade now will I have the 365 days +3 days remaining or will it default to 365?

 

Thanks