Looking for extension which fits my needs

I am using opencart 1.5.6.4.

I download a .csv file from my supplier. This is the (global) format:
* ItemId (Unique alphanumeric)
* EAN
* Name
* Description
* Price
* Stock level (can be "In stock", "Low stock", "No stock", "Not on sale" or "for pre-order")
* Producer
* Category (alphanumeric)
* Sub-category (alphanumeric)
* Product type
* Language
* Release date
* Image URL

Here are my requirements:
* I would like to edit the price (multiply by some factor)
* Stock level should not be overwritten, new products should start with 0 stock.
* Automatic download and process of the .csv file
* Images downloaded and displayed locally

Which add-on will fill my needs? I've tried a few from the marketplace, but the ones I've tried don't exactly fill my needs, and some have a demo-backend which won't allow me to import my file.

You will have to find a Developer, when it comes to write Custom Extensions, so, better place such inquiries in the commercial Section of this forum.
Ernie