Magento display current category level, parent and grandparent - php

Question

We have a magento 1.9 installation and on the left side we want to have 3 level categories to display as shown in the attached image (the breadcrumbs image is to show the levels). Currently I'm able to get the current category and his parent.
Below is the example of how I want it.
Could you help me out on this?
This is the code we have so far
<?php
$level = $this->getCurrentCategory()->getParentCategory()->getLevel();
if($level > 1){
echo '
<p class="back-to-parent">
<a href="' . $this->getCurrentCategory()->getParentCategory()->getUrl() . '">
<i class="fa fa-arrow-left" aria-hidden="true"></i> ' . $this->getCurrentCategory()->getParentCategory()->getName() . '
</a></p>';
}
else{
//
}
?>
<?php if ($categories = $this->getCategoriesNavMenu()): ?>
<div id="sidebar-nav" class="block sidebar-nav-left <?php echo $this->getBlockAlias() ?>">
<button type="button" class="btn visible-xs btn-block btn-primary" data-toggle="collapse" data-target="#sidebar-nav-content">Meer categorieën <i class="fa fa-filter" aria-hidden="true"></i></button>
<div id="sidebar-nav-content" class="collapse">
<div class="block-content">
<ul id="sidebar-nav-menu">
<?php if ($this->showHome()): ?>
<li class="<?php echo $this->getHomeClasses() ?>">
<span class="category_name">Home</span>
</li>
<?php endif; ?>
<?php echo $categories; ?>
</ul>
</div>
</div>
<?php if ($this->getConfig()->isCollapsible()): ?>
<script type="text/javascript" language="javascript">
//<![CDATA[
Codnitive = {
expandMenu: function(parent)
{
var mode = parent.getElementsByTagName("ul")[0].getAttribute("expanded");
(mode == 1) ? Codnitive.collapse(parent) : Codnitive.expand(parent);
},
expand: function(parent)
{
parent.getElementsByTagName("ul")[0].style.display = "block";
parent.getElementsByTagName("span")[0].style.backgroundPosition = "right center";
parent.getElementsByTagName("ul")[0].setAttribute("expanded", "1");
},
collapse: function(parent)
{
parent.getElementsByTagName("ul")[0].style.display = "none";
parent.getElementsByTagName("span")[0].style.backgroundPosition = "left center";
parent.getElementsByTagName("ul")[0].setAttribute("expanded", "0");
}
};
//]]>
</script>
<?php endif; ?>
</div>
<?php endif ?>