See the Wikipedia article on Sensitivity and specificity. It would not be difficult to write MATLAB code to do what you want. You would likely need to use element-wise operations, so see the documentation on Array vs. Matrix Operations to understand how best to do that.
There are MATLAB functions to plot the receiver-operator-characteristic (roc, perfcurve, and related functions), however they do not use the information you already have. There are File Exchange contributions as well that you might want to consider.
