XML and booking for Hotel Accommodation - travel site

Hi,
The basic platform is based on word press with some Travel Services already listed.
The functionality of the a travel related site (intro and categories pages)
with the search booking engine (based on the XML requirements from HotelsPro) will be integrated into the same back end - admin panel.
When a customer searches, the system must first go to the db and list own hotel inventory and then go to XML providers.

The solution ( WP based) must be extensible and able to get new hotel inventory of our own, (must be extensible for future developments – new hotel providers or new services like ticketing - and all other necessary stuff to fully operate as an e-commerce platform with checkout built in – Payment Gateway in multi currency (the different prices must be presented in the products page as well).
XML integration with the first provider HotelsPro
XML integration with Villa Rentals provider
Ability to include more providers in the future and services like ticketing in the future
Final design of the travel agency (we make the scripts and design the images) Assistance from freelancer on technical issues.
Expected timeframe : 1 week