Translation:Are you going to be at your house tomorrow?
Yes, estar does mean to be. But, the phrasal future tense is formed by using conjugation of "ir" and adding "a" + verb infinitive. (Yo) Voy a estar = I am going to be (or Am I going to be?) (Tù) Vas a estar = You are going to be (or Are you going to be?) (Él) Va a nadar = He is going to swim (or Is he going to swim?) (Nosotros) Vamos a dormir = We are going to sleep (or Are we...) (Ellas) Van a correr = They are going to run (or Are they going...)
[If you scroll down on the main page, this set of lessons has an explanation of the phrasal future tense.]