Expert in Public Relations, facebook, youtube, twitter, instagram, etc.
There are a lot of ways..LinkedIn can help greatly and even for that matter freelance sites like Elance, Guru, etc if you are tight on budget.
Specialist outsourcing company can be of great help but finding them can become tricky at times. I happen to use TechCusp.com for my company and although I was not very sure of performance, I was pleasantly surprise by the results shown by them in the last 3 months and that too at a decent cost.
If you need any help, feel free to reach out to me.