Why is Facebook giving us likes from other countries after Boosting Post?

We created a Facebook page for a computer optimization software that we are selling. We decided to offer a free thirty-day trial, so we announced it on Facebook. But it did not go to all of our fans, who had been anticipating the release of our trial. After researching this, we decided to boost our post, as we had read that Facebook somehow limits business posts so that way businesses will have to pay to "boost" their posts in order to reach their fans.

So after we spent $5 in order to do this, our post's reach increased from 8 to 1,100. However, I still think that many of our fans did not get the post. In addition, when we finally got some likes for our PC-Popper software page, the likes came from people with very strange names and even some people from out of this country. We wouldn't necessarily mind that our post reached people from out of this country since we are willing to sell our software out-of-country, too. However, we specified that we wanted our audience to be in the United States. So how and why did this happen? Also, when we went to one person's page who had liked PC-Popper, it said that he had liked a lot of other computer software, one within seconds of liking ours.

Our software is a really good computer optimization program (it really does what it says it is going to do, and we do not harass customers who download our trial to buy the full version), but we feel like Facebook is making us look like other software that are scams (e.g., RegCure Pro, Optimizer Pro, etc.).

So my question is this? Does anyone know what Facebook is really doing to "boost posts"? Also, what is the best way for us to actually reach the people who are wanting to use our software on their computers?

We appreciate any help.

Thanks