I'm going to echo what Blake said about the weightlifting shoes and staying on the ground a little longer.
First, weightlifting shoes are essential -- there's no other way to put it. The stability you get from them and the improved position you're in as a result of wearing them are incomparable to the shoes you're wearing now. I almost feel as though if you had them on, you'd actually stay on the ground a little longer ...
Still, to work on staying on the ground a little longer, work on pulls from either the floor or blocks, and work on tall/dip snatches and cleans. These will help you not only stay on the ground longer due to the decreased pulling range, but also help you with your turnover.
Lastly, here are some websites to get some shoes:
1. Some relatively inexpensive shoes that a friend of mine bought and enjoys: http://www.maxbarbell.com/collection...tlifting-shoes
2. A line of different brands that Rogue offers: http://www.roguefitness.com/shoes/we...FaTm7AodhioA3A
3. Risto Sports: http://www.ristosports.com/
Hope this helps!