Custom Interspire Shopping Cart Job

I need someone that can help me with my interspire shopping cart site.

Here is what needs to be done:

* Custom checkout
* Limit the number of products per order
* Recurring Billing
* Integration with Quickbooks Merchant Account

This is basically it, I will discuss in more detail with interested parties.

The site design is done, it is just not working like we need it to.

Thanks