I have two div that have to be in fixed so that they always stay at the top of the page, but the div above is eating little space of the div that has the menus.
What you should do is give a top to the header that equals the height of the top bar, so you will not get it covered.
.inheader {
position: fixed;
margin-left: 11%;
width: 75%;
top: 13px;
}