Edit in JSFiddle

#head_wrap {
    position: relative;
    top: 7px;
    left: 7px;
}
 
#crystal { 
    position: relative;
    background: url(../images/crystal3.png);
    border-top-left-radius: 45px 27%;
    border-bottom-right-radius: 45px 27%; 
    height: 117px;
    width: 100%;
}
 
.shadow {
    box-shadow: #333 0px 1px 1px 1px;
    -webkit-box-shadow: #333 0px 1px 1px 1px;
    -moz-webkit-box-shadow: #333 0px 1px 1px 1px;
    -o-webkit-box-shadow: #333 0px 1px 1px 1px; 
}
 
#logo {
    background: url(../images/logo_trans_p.png) no-repeat;
    float: left;
    height: 103px;
    width: 70px;
}
 
#titulo {
    color: white;
    font-size: 35px;
    float: left;
    padding: 0px 10px;
    height: 70px;
    width: 88%;
}
    #titulo p {
        margin: 0;
        padding: 0px 120px;
        font-size: 20px;
    }
 
#menu {
    background: rgba(77,76,77,1);
    background: -moz-linear-gradient(left, rgba(77,76,77,1) 0%, rgba(245,245,245,0.1) 70%, rgba(245,245,245,0) 78%);
    background: -webkit-gradient(left top, right top, color-stop(0%, rgba(77,76,77,1)), color-stop(70%, rgba(245,245,245,0.1)), color-stop(78%, rgba(245,245,245,0)));
    background: -webkit-linear-gradient(left, rgba(77,76,77,1) 0%, rgba(245,245,245,0.1) 70%, rgba(245,245,245,0) 78%);
    background: -o-linear-gradient(left, rgba(77,76,77,1) 0%, rgba(245,245,245,0.1) 70%, rgba(245,245,245,0) 78%);
    background: -ms-linear-gradient(left, rgba(77,76,77,1) 0%, rgba(245,245,245,0.1) 70%, rgba(245,245,245,0) 78%);
    background: linear-gradient(to right, rgba(77,76,77,1) 0%, rgba(245,245,245,0.1) 70%, rgba(245,245,245,0) 78%);
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#4d4c4d', endColorstr='#f5f5f5', GradientType=1 );
    position: relative;
    float: left;
    margin-left: 5px;
    height: 30px;
    width: 88.5%;
}
 
#menu a { color: white; text-decoration: none; }
 
#boton {
    float: left;
    text-align: center;
    padding: 5px;   
    width: 15%; 
    transition-duration: 0.2s;
}
 
#boton_r {
    position: absolute;
    bottom: 0px;
    text-align: center;
    padding: 5px;   
    width: 15%; 
}
 
.cotizar {
    background-color: transparent;
    color: #fff;
    float: right;
    text-align: center; 
    z-index: 1;
  
}


.fondo {
    background-color: red;
    border-bottom-right-radius: 100px 80px;
    position:absolute;
    right:0;  
}
 .tamano { height: 100%; width: 200px; }
.trans { opacity: 0.5; } 

<div id="crystal" class="shadow">
   <div id="head_wrap">
       <div id="logo"></div>
       <div id="titulo">Titulo<p>Slogan</p></div>
       <div id="menu">
           <div id="boton"><a href="#">Inicio</a></div>
           <div id="boton"><a href="#">La Empresa</a></div>
           <div id="boton"><a href="#">Servicios</a></div>
           <div id="boton"><a href="#">Contacto</a></div>
              <div class="cotizar tamano">Presupuesto</div>
              <div class="fondo tamano trans"></div>
      </div>
   </div>
</div>