first of all you need to drain your tofu. cut the tofu into 1" thick slabs, and place them between folded paper towels. using something as a weight (a plastic container filled with water works well), place the weight on the tofu, and let the tofu drain out it's liquid. you may have to change the paper towels a couple of times. cut the tofu into 1" cubes, and lightly dust with corn starch. deep fry the tofu until golden brown, then toss with your stir fry. in essence, you need to cook your tofu seperately. the coating on the tofu will soak up the sauce when you toss it, and the tofu will stay firm and hold it's shape
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Johann Wolfgang Von Goethe