Adjust current reward website

I have a newly created website that needs some tweaking. This site is designed for ecommerce incentive rewards program. The site is located at capitiolmarketingsolutions.com. The original coder did a fine job but I find several items I need changed are the following: Registering and login is extremely confusing. I want to have one Login that requires all information to be captured and can be used for returning customer and same information for the cart with a button stating use the current information and it populates with their current information or allows for a different shipping location. Instructions would state this in startup page, login page, and cart page. Also arrange the Information on login and in the cart to read in this order: Asterisk is mandatory before moving on: Last Name * First Name * Address * Address 2 City * State * Zip Code * No country Certificate Number (On initial login only). * The administrator section allows me to change the logo now, would like to also to change background color with a color palette or an image that I can change for a customer appearance. I need this system to be moved easily to as many sub-domains as possible, and would like you to do three for me immediately after all fixes are in place. I want this to occur without damaging or having to rebuild the database. Must work with all browsers.