It sounds like you are not making money, so either A) fix something so it makes money or B) toss it.
Just because something is useful does not mean it is profitable. As with all things in business, you have to find someone that values your service enough to pay for it (in some capacity).
I wanted to write software for academic biologists because I'm an ex-biologist...but they don't want to pay for it. Doesn't matter how useful it is if no one is willing to pay.
So, shut it down. Kill it with fire and move on.
At the moment, $1700 in donations (edit: and a few links/promos generating traffic) would convince me to keep it up for another year. That would not get me off the street but it would pay my taxes, pay the webhosting and domain name and help me and my kids eat properly for the next two weeks. In other words, it would alleviate some serious immediate stressors. But no one will blog about it and announce it to the world and tell people to support it or open their own wallet up. So I think I will try the e-book idea and then move on to other projects with an eye towards making money first and foremost.