I'm sort of new to this myself, and I'm not at home to access Cakewalk so this is from memory. If I recall correctly, when you add the eq effect you should be able to access a setup screen for it (by double clicking on the effect's name in console view).
In the lower right part of the setup screen are 4 square buttons labeled 1-4 representing 4 preset frequencies. If you click on one of these buttons a corresponding dot will show up on the eq graph in the upper left. Click and hold on the dot and you can sweep it right or left to sweep the frequency, or up or down to raise/lower volume. As you already figured out, you can also set the bandwidth for each of these 4 eq points.
Hope this helps.