Switching from Individual to Families (going through Billing doesn't work)

Hi, I'm trying to upgrade my Individual account to a Family account.  The Help instructions are easy: Log in, go to Billing in the side bar, choose your upgrade option and select Switch Plan.  Problem is when I go into Billing I don't have any upgrade options.  Instead it gives me a link to go to the iTunes store and when I do that iTunes just gives me basic info on my subscription with no option to upgrade (only cancel).  So how do I change to Families in the simplest way possible?