First get your product collection. For example, here the collection is `$merged_collection`. then apply the following code in the position where you want to place the pager and toolbar.

    <?php  
    $layout = Mage::getSingleton('core/layout');
    $pager = $layout->createBlock('page/html_pager');
    $toolbar = Mage::getBlockSingleton('catalog/product_list')->getToolbarBlock();
    $toolbar->setCollection($merged_collection);
    $toolbar->setChild('product_list_toolbar_pager', $pager);
    echo $toolbar->toHtml();
    ?>