Magento: customize Low stock report

Question

Hey folks,

I need to add a few, sales-related columns to the Low stock report (e.g. Sales last week, Sales week before last week etc.)

How should I do this?

I’ve already managed to add some basic columns which already exists in the Collection (e.g. price, status etc.)

I’m looking at Mage\Adminhtml\Block\Report\Product\Lowstock\Grid.php and at the_prepareCollection() method.

I can loop through the $collection but how am I supposed to add to this additional data?

The _prepareColumns() method is straight forward.

Thanks for any suggestions