Yes it is a new museum, in the south of Cairo east of the Nile.

I don't know what they're planning to do with the old museum. As you say, it's a beautiful building; it's also historically important, if only for the role it's performed in housing those amazing artifacts. So hopefully they do keep it in use.

I know I'll be going back by even if it's not, just to remind myself of the morning I spent there.