So what I understand is your sub menu doesn't come on top of the blue bar, but instead, is seen under it. That could be the problem, but need not be.
You'll need to find the CSS class used for the sub menu (something like firebug on Firefox will help you here, or IE developer toolbar in IE), and then check the following:
1) If there's a background colour set anywhere. If not, add it
2) the z-index of the sub menu. If its no >= 1, then increase it. If there is no z-index, try adding it to 1 or 10. Check the z-index of the logo image. If there is no z-index, don't worry about it. If there is, you need to make sure that the z-index of the submenu is greater than the z-index of the logo image.