my forum is on the premium package, and I have enough credits to add another year of premium package,

but I don't see how to do so.

my package will expire in about 140 days and I worry about losing my domain name and premium features.

Hello,

You may have to wait until you get closer to expiration. I would say within 60 days of expiration you definitely should be able to renew it.

-Brandon

It can also appear about 60 days before it expires.  That is what happened on my forum.