Magento Website Edit - Auto stock status on product and category page

General information for the website: Retail website
Description of requirements/features: We need the stock status to change automatically depending on the stock value within Magento. It should follow these rules:

0 or below = Out of stock
1 to 500 = In stock
501 to 1000 = Available
1001 to 1500 = in stock
1501 to 2000 = pre-order
2001 to 2500 = in stock

I have attached some designs of how this should look. It involves some changes to the product page to include:

Move SKU
Add tick or cross logo
Add In Stock or Out Of Stock text
Add countdown timer for delivery


Here are more details per stock graphic:

In Stock - Countdown to 5pm every working day. Excludes bank holidays. Displays the next working day as the delivery day. Example - If ordered before 5pm on a Tuesday it will display Wednesday. If ordered after 5pm it will display Thursday. After Friday 5pm it counts down to Monday 5pm.

Available - Sent within 1-3 days via our economy delivery service. Delivery day is 4 working days from current day before 5pm. So if it is Monday before 5pm it shows Thursday. If it is after 5pm it shows Friday.

Out Of Stock - No countdowns just normal text

Pre-Order - Date shown should be as New date in backend of Magento


Website currently live at demogear4djs.co.uk. I have attached mockups of the design. Category page design attached as well. This shows the stock status icon depending on the same rules above. On the design attached the products are from left to right: In Stock, Available, Out Of Stock. Pre-Order will display like the middle product but the Add To Cart button needs to change to PRE-ORDER.
Extra notes: Full design mock ups and graphics available