Regarding the issue with the joomla update we can't help much, but regarding the issue with the tabular layout, it seems that you're missing the new CSS code for the tabs in your frontend CSS file of HikaShop that you can edit via the Display tab of the configuration:
#hikashop_tabs_div ul{
z-index: 2;
position: relative;
margin: 0px 0px 6px 0px;
}
#hikashop_tabs_div li{
display: inline;
background-color: #fcfcfc;
padding: 8px 5px;
border: solid 1px #E7E7E7;
z-index: 2;
font-weight: bold;
}
#hikashop_tabs_div li a{
color: #555555;
}
#hikashop_tabs_div li a:hover{
text-decoration: none;
color: #555555;
}
.hikashop_tabs_content{
z-index: 1;
position: relative;
display: none;
min-height: 200px;
background-color: white;
border: solid 1px #E7E7E7;
padding: 5px;
-moz-border-radius-topright: 4px; -webkit-border-top-right-radius: 4px; -khtml-border-top-right-radius: 4px; border-top-right-radius: 4px;
-moz-border-radius-bottomright: 4px; -webkit-border-bottom-right-radius: 4px; -khtml-border-bottom-right-radius: 4px; border-bottom-right-radius: 4px;
-moz-border-radius-bottomleft: 4px; -webkit-border-bottom-left-radius: 4px; -khtml-border-bottom-left-radius: 4px; border-bottom-left-radius: 4px;
}
.hikashop_tabs_li_selected{
border-bottom: solid 1px #ffffff !important;
background-color: #ffffff !important;
}
.hikashop_tabs_li_selected a{
color: #1491B0 !important;
}