Back to the grind?

Right now I'm trying to figure out what my job situation will be like in the fall.   My old boss has been writing me and asking me back to my job.   He's such a great person to work with and he's since been promoted to a regional director.  

Now, I'm in the middle of negotiations and trying to get more money.   Ideally, I would only be able to work M,W,F 8:30am-1:45pm.    That's only 15 hours a week.   Then I could do the computer work sometime in the afternoon.    That would probably bring me right around 20-25 hours per week.