A search engine will be the best database in this circumstance. Your inquiry is specific enough that any firm meeting your criteria should be easily discovered through a combination of carefully selected keywords. Any firm not revealed either (1.) doesn't fit your criteria, or (2.) has no real understanding of online marketing. If they can't do it for themselves, what would make you think they can do it for you? Trust your search engine.
If your company culture hasn't yet embraced the power of social media, it is at risk of getting steamrolled by competitors. Here are four tips on staying in the game and building a more social business.