I have heard it recommended that if you plateau for too long, then its a good idea to slowly increase calorie intake up to maintenance level - increase daily intake by around 200 calories a week, then eat at maintenance level for a few weeks, then gradually cut back down again to weight loss level. ie - try and fool your body into thinking that you've stopped trying to lose weight.
Another thing that is really good for fat loss is high intensity interval training - instead of doing half an hour at a steady pace, do 15 minutes of alternating easy/all out effort. Your fitness will improve dramatically!
Hope this helps, you already sound like you've gone down the right path in trying everything, and congrats on your weight loss!
I am gonna exercise my butt off!! Literally!!