Migrate Existing eCommerce Website to Drupal

The existing site is built using an antiquated CMS called mySite.
Products are uploaded / updated though a csv file generated through our external fulfillment / stock management system (v. adaptable). No images are configured or stored through the sites CMS. The product csv includes a description field which has pre-generated html pointing to image library stored externally. Ideally this functionality would be adapted to the drupal site- with csv upload / refresh working in a similar way.
HTML on Pages on the old site are also generated externally and manually updated when necessary - through the same system that creates the csv. Would want drupal to to do this.
6 product groups, approx 250 product variants.
Drupal Installation already configured on BlueHost.com
Main task is to recreate existing look and feel, and ensure that existing product csv data can be adapted fairly easily to work in new site. Image library to remain unaffected. We have in-house IT support who are v. familiar with these systems and will help with configuration.