Here's my opinion, build another app, or better yet build 3 other apps and diversify your income. 1 mobile app is not enough to require full time dedication, but having 3 or 4 apps to cycle between will keep you busy and should provide good money.
I wish I had the insight to know exactly what 3 or 4 other apps to write so I can have a steady income. But chances are by the time I finish writing 3 good apps a year from now, I'll be lucky if one of them has as much traction as this one.
The other choice would be to take this app that already has traction (from only my part time work) and pour more time an energy into it to see how big it could really get.
Thoughts?
1. I have one good app in dev process in a market segment that is hot, Custom HomeScreens
2. I know that I need some more apps, was thinking some quick 2d games via using andengine.
3. I do have some fulltime inquiries that might work as base income to fund the full 12 month weekend-evening dev cycle.
Pull Tim Bray's recent blog posts on making money in the android market. There also was some recent HN articles on android dev's making $120,000 yearly with a paired free and paid approach.
BTW, what dev processes are you using thus far? I am switching to combination TDD and BDD approach using robolectric and robotium/android-mock to take some of the pain out.
I have no tolerance for bugs, bullshit, or shitty customer support. Emails are answered within a day but usually hours, sometimes bugfixes even come out in less than an hour.
I don't unit test, I just write good code ;) Seriously, none of the bugs I've encountered were really unit-testable, so I don't really bother.
I really wish we had a few more folks hacking on Android! cough we're hiring cough :P