Free samples system

Hi,

I need an Opencart modification, like this which allows people to order some free samples:

1. If shopper has added products from "Samples" category to their basket they will be required to register (or login) - no guest checkout is allowed - the reason why is explained below.

2. The customer should not be allowed more than 5 samples in their basket for the order.

3. The customer can only place an order for samples once every 90 days (after 90 days a scheduled task should reset this so they can order again).

Can anyone help me with this?

PM sent.