Create Sale Report - XLS Export

I need a sales report creating, it will list all the products then output how many where sold on each individual channel and in total as well as the average across the last x amount of months.

Approximately 1800 products to be listed.

I have tried using a PHP script however it takes 10 - 15 minutes to run which causes the page to time out, I need this to be completed and outputted to an XLS file in less than a minute, how it does it is entirely up to the developer.

I have pasted a link below the layout it needs to be exported into; this must be an XLS and created to look exactly like my example.

http://www.shaunswales.co.uk/wp-content/uploads/2014/06/Stock-Sold.xlsx

The script allow you to set how many months back you are wanting to search and the calculate which orders are taken into account.

This should take an experienced developer no longer than 1-2 hours.

Please quote fairly.

I look forward to hearing from you.

Thanks,
Shaun Swales