Ug! I hate plateaus!
There are two main things I do to break a plateau.. First, with eating -- I increase my Calories for a day or two.. Add an extra serving of olive oil to your food (I think it's 120 Calories per tbs, but don't quote me on that), or maybe a serving of low-fat cheese (around 90 Calories).. Sometimes our bodies greedily hold on to fat because our Calories have dropped too low. Adding slightly more of an "approved" food for a day or two is often enough to nudge things in the right direction.
The second thing I do is follow the FIT method for exercise. That is, Frequency, Intensity, and Time -- frequency would be adding an extra session per week, intensity is adding resistance (I like those strap-on weights myself), and time is exercising for longer each time. Often one or all of these are enough to kick start things when they stall