At present you have a table with one tr tag (row) and three td tags (cells) which are always in the same row; so what you have to do is to add in more <tr> and </tr> tags between the cells to split them into different rows:-
<table border="0" width="100%" cellspacing="0" cellpadding="" class="productListing">
<tr>
<td align="center" class="productListing-data"> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=1&osCsid=85186e9e6694375b8727baae354cad52"></a> <br> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=1&osCsid=85186e9e6694375b8727baae354cad52">0800774424</a> £10.00 <a href="http://www.dialnumbers.co.uk/secure/index.php?action=buy_now&products_id=1&cPath=1&osCsid=85186e9e6694375b8727baae354cad52"><span class="nowrap"><span class="template-button-left"> </span><span class="template-button-middle">Buy Now</span><span class="template-button-right"> </span></span></a> </td>
</tr><tr> <!--these have been added-->
<td align="center" class="productListing-data"> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=2&osCsid=85186e9e6694375b8727baae354cad52"></a> <br> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=2&osCsid=85186e9e6694375b8727baae354cad52">0800774425</a> £10.00 <a href="http://www.dialnumbers.co.uk/secure/index.php?action=buy_now&products_id=2&cPath=1&osCsid=85186e9e6694375b8727baae354cad52"><span class="nowrap"><span class="template-button-left"> </span><span class="template-button-middle">Buy Now</span><span class="template-button-right"> </span></span></a> </td>
</tr><tr> <!--these have been added-->
<td align="center" class="productListing-data"> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=3&osCsid=85186e9e6694375b8727baae354cad52"></a> <br> <a href="http://www.dialnumbers.co.uk/secure/product_info.php?cPath=1&products_id=3&osCsid=85186e9e6694375b8727baae354cad52">0800774426</a> £10.00 <a href="http://www.dialnumbers.co.uk/secure/index.php?action=buy_now&products_id=3&cPath=1&osCsid=85186e9e6694375b8727baae354cad52"><span class="nowrap"><span class="template-button-left"> </span><span class="template-button-middle">Buy Now</span><span class="template-button-right"> </span></span></a> </td>
</tr>
</table>
That will put them one above the other, but the width will be too great; with table width="100%" you will probably get the same total width of table but each cell will fill the whole width (and normally it will be in the center) so you may have to do some more work to get it to look good.
Delete the <br> tags in each td cell which cause the next part to go to the next line, then each item will only form one line (I've done it in my code above between the number and the price and Buy Now but there is another <br> tag in each cell which may also need deleting).
You may also find that there isn't enough height to have them one above the other unless you delete the <br> tags like I have, affecting items underneath, but experiment.
I'm not sure how the above links with CRELOADED; perhaps you have to do the edits in that program.