Since Flora Singer's PTA was recently part of Oakland's, they probably follow the same procedure (although I haven't confirmed). The PTA offers the after school enrichment. They organize the classes and then send a packet home mid-September with the options. Sometimes the handouts don't come home all at once - it depends on how fast the parent volunteers gets the dates/times set up and sometimes you get an email.
This is what was offered last year (
http://singerpta.org/sites/default/files/PTA%20After%20School%20Fall%202012.pdf) so you could probably contact the PTA if you don't hear about an activity by mid-September.
As for start time, PP is correct. Most of the activities start in mid-October. If you need aftercare, you would have to see if KAH has openings.