Hi, judging by your circumstances, my suggestion is to hire a part-time PR consultant to come up with a strategy for you. He/she should understand your industry and help shape campaigns for you. PR agencies are generally busy and will devote more time to bigger clients. Is there a communications/marketing person taking care of your social media at the moment? He/she should have a clear idea of who your target audience is and their behaviours. He/she can work on implementing the strategies. E.g hiring a copywriter for press releases or help liaison with events etc.
One mesurable objective is the surge in traffic that leads to sales. This tends to happen after media exposure and successful campaigns.
I am a PR and Branding consultant working in London. My clients and myself have appeared in the BBC, Guardian, Observer, SkyTV, Yahoo News, Huffington Post, Wired and various medias around the globe. I have also helped raise over half a million in funding for clients.
Contact me and I will give you some websites for doing your own PR online.