you need to have some sort of social marketing campaign.. either using facebook ads, or offer some sort of viral app like quizes, sweepstakes, games etc. You can also buy facebook fans/likes, but that's not recommended for businesses.
On a sidenote...If you are interested, I do have a unique viral facebook app with a much higher roi and way way cheaper than any other alternatives.
screenshots :
http://imgur.com/a/Fr8lg
I can't go into details about all the features here, too long. Message me for more info and a demo. Btw, if you are seriously, i can make 1 for you to try, you only pay me if you are happy with it.
I can customize this to your requirements, including design, layout, your name/logo, adding more features. I can add easter eggs, like user post a link or message about you, and unlocks certain features. Plus a nagging screen at the bottom that goes away if they like you page, or become a fan.
It is a viral app, but doesn't spam, it's clean and ethical. We are talking building long term relationships with your users.
This is a desktop app that's meant to be use everyday, so your brand/bannder appears in front of the user everytime they use it...on their desktop, no competition from other ads.
Even if they don't buy anything from you, you'll get traffic to your website/blog, and they'll sure remember you. You can't get this type of roi with ads, or apps like quizes or games, that are meant to be used only 1-2 times.