First off, best of luck with the upcoming launch!
Now about Facebook, as a rule of thumb, Facebook 'likes' are a bad KPI. Because the amount of organic exposure Facebook allows 'pages' has become very low. ( 16-18% I think is the estimate. )
The idea is you use Facebook to isolate a specific customer segment and direct them to actions that generate revenue.
Usually Facebook likes do not generate revenue.
So here's what I suggest you do.
1. Describe your perfect customer. Use any relevant parameters like age, sex, location, interests, etc.
2. Decide upon a 'call to action'. The specific action you want your ideal customer to take. Preferably an action that generates revenue.
3. Design a Facebook ad, that speaks directly to your ideal customer at the center of which is the action you want them to take.
Every campaign consists of one ideal customer and one call to action. If you have several customer segments in mind, or several call to actions, create several campaigns.
Hope this is helpful!