Too much cardio and not enough HEAVEY weights. Lighter weights won't really achieve what you want. Do cardio for sure but mix it up with steady state cardio and HIIT.
With your diet, rather than focus on calories I'd focus on 'eating clean'. You know what they say: abs are created in the kitchen.
On another board someone has questions about why her routine (in which she does cardio 6 days a week) isn't working and the responses might help you. The link is:
http://www.oxygenmag.net/showthread.php?t=31449
Now, I need to take the above advice, I tried on a pair of jeans today and they were a little more...mmm...snug than I'd like.