I am not sure burning your marketing budget on a single source was the best decision, especially when that source is Facebook.
When starting, it is best to make a rule to always research the topic. Hundreds of companies before you have spent a lot of money advertising in all kind of ways, from traditional advertising to search engine techniques. A lot of them share their experiences in professional communities, or in blog posts. Some studies are posted by specialty media. After looking at a number of them, it seems to me that the general consensus in regard to Facebook is that it is an ineffective method in converting sales. You would have probably seen the same feedback and reports if you were to scan forums like ours for similar questions.
My suggestion to you today is to diversify as much as possible. Separate your budget in 4 different baskets, for example, run advertising (at times this advertising would not cost you anything but your time, when it comes to social - forums, social media, etc.) and assess results. Wherever you see best results, increase its budget. When things don't work, cut them out of your marketing equation.