Product reservation - need coding for feature

Our website at http://www.techmonkeysolutions.com/rentdemo is catered for jewellery rental purposes.
Customers should be able to place a booking for an item based on a selected date range ( eg: from 1/10/2013 to 5/10/2013 ) and based on stock availability
Upon checkout, Opencart should be able to calculate the total rental fee payable by the customer based on his selected date range
However, Opencart Admin should have the flexibility on the admin panel to change the reservation dates; if need be


What We Have Now
- Opencart Reservation - by webfryslan installed
- However, this extension does not allow booking of an item based on a date range ( eg : from 1st Oct to 5th Oct ) – similar to how hotel reservations work.

Conditions of Booking
Prices stated for the items are for a standard 3 days rental period. Additional day would be charged at $6 per day


Example Scenario
Person A – places booking of item A from 1/10/2013 to 5/10/2013
Person B – is only able to place booking of item A from 10/10/2013 – 12/10/2013
a) The example above shows the availability of item A, given there is only 1 stock of that item.
b) Days between 6/10/2013 to 9/10/2013 are basically admin processing days, which takes 4 days to complete.
c) When Person A’s rental period ends on the 5/10/2013, he will then post the item back to the owner on 6/10/2013. Between 6/10/2013 and 9/10/2013. the owner will then receive the item back, validate the item for any damages, and refund the deposit paid by the customer through a manual bank-in process. Hence, 4 days of admin processing days needs to be considered for each product reservation – however admin should be able to change this date on the backend
d) Once the process in ( c ) completed, the item would be made available for reservation from 10/10/2013 onwards.
e) We also need to block certain days for public holidays and this is to be done through the admin module.
f) If the item return date falls on a Sunday or Public Holiday, the 1 day fee of $6 should be charged and shown upon checkout.


Would appreciate if anyone can provide us the estimation effort to be able to do the changes above based on the current extension we have.

This should have been posted at the Commercial Support section, not here!

This all wil be included in the 2.0 version of Opencart Reservation. Release date for that version will be 6 december 2013

I published a prerelease where the from-till option is working at :

http://www.opencart.com/index.php?route ... n_id=11323