You really should study more the extension system between the template parts.
For example you have
catalog/listing/category.tpl
which extends
catalog/listing/product-list.tpl
You have to add a block like this
{block name='right_column'}{/block}
But with a UNIQUE name e.g.
{block name='greek_mod'}{/block}
Then you call it in category.tpl and make the respective alteration.
NOT tested, but it should work. Always backup 😎
You really shoul study more the extension system between the template parts.
For example you have
catalog/listing/category.tpl
which extends
catalog/listing/product-list.tpl
You have to add a block like this
{block name='right_column'}{/block}
But with a UNIQUE name e.g.
{block name='greek_mod'}{/block}
Then you call it in category.tpl and make the respective alteration.
NOT tested, but it should work. Always backup 😎