I saw a bumper sticker recently that read something like this:
"Decisions are made by those who show up".
Having once lived in a condo community and worked on a condo board as well as having been board president for many years, I can tell you that it is a thankless time consuming job that very few people appreciate. Yet I did it for 13 years and found it to be a great learning experience.
That being said, your community has to come together in order to protect it's investment.
I would recommend getting together with the remaining board members and anyone else who is interested in joining and meeting informally (over coffee at your house for example) to develop a strategy. You need to communicate what is happening to the rest of the community - door to door if you must - to drum up interest.
You might even want to gather people together at fun informal events to build community spirit which sounds like yours is lacking of late. Folks are more likely to show up at a block party on the weekend vs. a meeting late at night after work when most are too tired or need to get the kids down to sleep on a school night. Once people can put a face to the name and get to know each other, most will now interact more comfortably and be able to discuss issues without yelling. Building trust is key.