Code in customer tier system to our BigCommerce shop.

We currently operate a Big Commerce shop selling engineering tools. It is maintained by very amateur coders with limited skills and we need some assistance incorporating a reward / tier system for our customers. For example, if a customer spends over "X" amount of money (EXCLUDING SHIPPING) on our site, their member account is AUTOMATICALLY upgraded to a new tier. This new tier gives the member access to 5% discount off the rest of the products in our shop for a lifetime. Once that member reaches the goal for the next tier, their account is upgraded again and they receive new benefits and so forth. We would like it designed with the following hierarchy: Standard Member: Spent $0-299 in store. Receives no benefits. Bronze Member: Spent $300-599 in store. Receives 5% off storewide for all future orders. Silver Member: Spent $600-999 in store. Receives 7% off storewide for all future orders. Gold Member: Spent $1000+ in store. Receives 10% off storewide for all future orders. We'd like everything to be accurately and automatically calculated and we'd like the customer to have a page where they can view how much they have spent and how long until their next upgrade, view able from their My Account page. We'd also like to change it so when a user log's into our site, instead of the hyperlink changing from 'Sign In' to 'Sign Out', we'd like it to say, "Hello, *CUSTOMER NAME*!" and then display a small badge with their rank. More than happy to discuss the project in detail with those competent in completing it.