The correct answers are It's time we left this spooky house! and It's time to leave this spooky house!

When expressing that an action should happen right now, you can use "It's time" followed by a to-infinitive (It's time to leave).

Alternatively, you can use a subject followed by the unreal past / past subjunctive (It's time we left). This emphasizes that the action is perhaps a little overdue!

We never use object pronouns (us) before the past tense verb, nor do we combine a subject pronoun (we) with a to-infinitive in this structure.