Facebook reach has plummeted for most businesses over the last 12 months - the basic premise is they want you to pay for advertising and they're making it very hard to get any organic reach on promotional posts.
To maximise what little facebook exposure you can still get you need to generate customer interactions,.. if your posts get likes and shares then facebook will allow the organic reach to go further,.. if no one likes or shares then it'll quickly fade into the background.
Facebook is quickly becoming more hassle than its worth though - I've 1376 likes on my page and my posts rarely reach more than 130 of them at best,.. often its less than 80 people reached...