[revorad]

You could hire someone. I know you might find it hard to let go of your codebase and feel it's too complex, but there are plenty of good programmers out there.

You said you're concerned about how much it might cost. Surely you can afford to try someone out for a short amount of time, given the app makes $10K a year. If you shut it down or open source it, that income's gone anyway. So why not try to keep a good product alive?

One good place to look for a programmer might be the monthly HN threads by whoishiring - https://news.ycombinator.com/submitted?id=whoishiring