I am a programmer who sucks at marketing
That's the mission critical bug that will kill your business ;)
Read these three books ~many~ times:
-> The Four Steps to the Epiphany by Steve Blank
-> Traction by Gabriel Weinberg
-> No B.S. Direct Marketing by Dan Kennedy
Then split your overall time 50% dev, 50% marketing.
Plan B: keep an eye on the contracting market in your area of expertise ...
Good luck!