Also, check out my account of the same struggle. You may or may not find useful things there:
www.seabreeze.com.au/forums/Kitesurfing/Newbies-Tips-Tricks/Newbie-Lessons-learned-so-far/On reflection, if you're launching yourself face first, and you feel over powered, I found it was because: a.) I wasn't pointing the board down wind (i.e. the board was perpendicular to where the wind was pulling me, hence it didn't slide over the water and b.) i was pulling myself up using my arms to pull myself up on the bar, which in turn gives you too much power and slingshots you over the board. Let the kite pull you up through the harness.
Finally, looking back, if I knew what I knew now, I'd have practice water starts by going through the motions (board on feet, kite over to 1pm, then dive it down into water start position and back up) without pulling on the bar which gives you launch power. This would have gotten me used to what I needed to do with my arms and kite before worrying about the whole standing up, going along nonsense.
Good luck. You've picked an unfriendly time of year to start, and any progress you make now will put you in good stead for the spring/summer time.