Roshan, as one of the solutions I suggest keeping the menu in 2 lines but edit CSS a little bit so that everything fits in:
1. Add a height to .ow_header . About 180px (screen 1).
.ow_header{
background-image: url('images/top-bg.png');/** OW_Control type:image, key:headerImage, section:1. General Settings, label: Page header image **/
background-color: #f1f1f1;
background-repeat: repeat-x;
background-position: bottom left;
height: 180px;
}
2. Drop .ow_main_menu down. About -50px (screen 2).
.ow_main_menu{
position: absolute;
bottom: -50px;
right: 0px;
z-index: 1;
}