Dynamic Website / Portal with customized e-commerce solution

Small limousine service / sightseeing tours / shuttle services company in Portugal is looking to build a new website that will not only be a corporate presence but also offer the possibility for the visitor to make reservations online. The site must also be designed to take intelligent advertizing within the site. The reservations are date-dependent, type of vehicle-dependent, number of passengers-dependent, pick-up location-dependant, drop-off location dependant etc. The shopping cart should allow us to accept credit card payments, both online and offline as well as paypal and google checkout. The shopping cart must allow integration with a web-based invoicing software (via API) without a live operator dependancy. our idea is to provide a Joomla based template and work from there. The prices will be given to the system from an Excel spreadsheet - the system doesn't perform price calculations other than those. The website should also contain a feature of touristic information based on google maps for Portugal.