Build a Drupal site to sell financial products

I need someone to build a Drupal site to sell my financial products. The developer should have access to eye-catching drupal themes. Start with a customer portal to capture customer details and related information. It also should be able to integrate with Google sheet API. Google sheets hold all the foundation data, such as a list of products and institutions. Extensive knowledge of core drupal modules and webform and knowledge about performance tuning will be a great asset to the project.
I look forward to seeing your proposals with good working examples and references.