Please go to your calendar on the web version: https://tools.2houses.com/agenda, click on "Share my calendar" and follow the prompts:
While 2houses pushes out schedule changes immediately, Google Calendar updates on a 12 hour cycle for subscribed calendars, so you will need to wait for the next update. This means that depending on where you fall in the cycle, Google can take up to 24 hours to push the update to your subscribed calendar.