Time for what? Local recovery? Global recovery? Entire CNS adaption ?
As others have said, too many factors for a definitive answer. Bear this in mind:
its very, VERY, difficult to actually overtrain. By overtrain i mean in the 'physiological response' sense. Bulgarian weightlifters train max sq's, snatches, deadlifts and cleans twice a day, 6 days a week.
Circus - why not ramp up to 4 days/wk? You've started with 2, when you feel comfortable try 3, and eventually 4. Deload every 5 weeks or so, and watch out for symptoms that suggest you NEED to deload:
lethargy
lack of appetite
contant tiredness but inablility to sleep
irritability
lack of motivation