if your template is reasonably std. then the header is
<?php if (!empty($this->category->category_name)) { ?>
<h1><?php echo vmText::_($this->category->category_name); ?></h1>
<?php } ?>
so move the
// Show child categories
if ($this->showcategory and empty($this->keyword)) {
if (!empty($this->category->haschildren)) {
echo ShopFunctionsF::renderVmSubLayout('categories',array('categories'=>$this->category->children, 'categories_per_row'=>$this->categories_per_row));
}
}
below that
same for the clearly commented search block
templates\YOURTEMPLATE\html\com_virtuemart\category\default.php