You've been tasked to manage all the digital marketing - where do you begin? (here) And do you have to spend money? (NO)
While it might seem like an impossible task (digital marketing covers all things digital after all), taking a systematic approach at least makes it seem less daunting.
All the glory and attention in digital marketing is put on SEM/PPC/Display ads, and for good reason - they're relatively cheap, scalable and measurable. However, it's important to not fall into the trap of thinking that paid digital marketing is all there is to do, there are many FREE (or earned) things to get started on first.
Beyond the basics (understanding the audience, finding your USP and being present on the right channels), creating your own content is where you should be spending the bulk of your time. Creating your own content for social media (or your website) doesn't have to be difficult or expensive (but it usually does take time). However, it's key to think about the type of content and the quality of the story - you need to make sure that it caters to the exact audience you're looking to attract, because if they don't care, what was the point? This is the mistake most marketers make with content - they believe that if they build it, people will come. They couldn't be further from the truth.
Apart from content, you should also consider PR - it still works! Understanding that journalists and bloggers are starving for good content as well, and working with them to craft interesting storylines can go a long way. You might not have a strong audience/community, but they certainly do.
Finally, look towards your 1,000 true fans for help. They are going to guide you towards where you need to be more present and how best to expand your inner circle of fans. This could be community events you should be present in, ideas on cross-collaborations with other brands or branded opportunities you didn't know otherwise existed. It's better to ask and find out than wonder what could have been.