magento add on to shipping and invoice

Avg Bid (USD)
Project Budget (USD)
$250 - $750

Project Description:
I need to add a function in magento site that will display on invoice "Your Order will be delivered from {date} to {date}". It should function as below:

a) check zip code in the checkout. Currently using one step checkout.
b) compare it to datasheet and adds message: Your Order will be delivered from {date} to {date}
c) day will change.
d) Since I have multiple shipping methods it will add x amount of days, example

Assuming it is Sept.17

Home Delivery : +5 days - Your Order will be delivered from Aug.22 to Aug.24
2 Day: +2 days: Your Order will be delivered from Aug.19 to Aug.21

+ check against zip code

Data sheet

What I can do is to prepare a csv that I should be able to load to magento admin with data: Zip code | Shipping Method | Extra Days.

Skills required:
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