Customisation to WP Theme

The Templatic "Store" theme incorporates its own e-commerce functions for WordPress. The last released was in Jan 25, 2011 is found on [login to view URL], but requires 2 additional features for my e-commerce website: 1. For each product setup, there will be a checkbox to indicate whether the product is a prerequisite (or main) product. With this, the shopping cart will check its contents if any prerequisite product exists as soon as the buyer proceeds to checkout. If there isn't any, an error message will prompt the buyer to include at least one main product into the shopping cart. 2. Zone-based shipping option, in which the cost of shipping will depend on the zone (or area) that the items are sent to, regardless of their total weight. ** T&C: Amount bid here is final, which covers the complete delivery of the project. Any hidden and/or additional costs will NOT be entertained, and the violator will be immediately blacklisted. However, any add-on requests can be negotiated.