Your setup reminds me of my own on the Maillot Jaune. I purposely bought the frame slightly smaller for a more aggressive setup but found I had a hard time getting the bars up high enough for my comfort. What I found earlier in the year, when I was less fit, was that a lower bar height setup put more weight on my hands and was causing numbness and pain. By raising the bars a bit, I was able to ride longer distances more comfortably, which resulted in better fitness in the arms and abdominals, which in turn allowed me to return the bars to their lower, more preferred position.
I'd suggest either a stem with a higher rise or an adaptor that allows your current stem to be raised an inch or so. This would be a temporary fix at worst, so don't go crazy spending a bunch of money. Throw some extra situps and pushups into your regimen and before long, you'll be riding without pain on your current setup.
This picture shows the Maillot Jaune when I tried raising the bars but couldn't quite get it to where I really needed it. Nowadays, the stem is down to a normal height.
http://www.bikeforums.net/attachment...chmentid=17647
Good luck.
55/Rad