update and improve security on website

I want a website that is functionally equivalent to the following site, Nurse411 dot com. I want it to be secure (prefer database access to be changed to parameters for security purposes) with error pages and emails to me at errors at Nurse411.com. In addition to secure access using database, structure of which can be modified by you to make coding easier, I will provide the database as currently structured upon acceptance of your bid. Needs to be responsive and function on phones and tablets. Need to send email to customer when they make any purchase or register for any course, free or otherwise. Payments are all made through PayPal. Currently, that is functional. Also, the course are uploaded to [login to view URL] website, and that is currently functional. Need the course to be assigned to customer after purchase/registration and need the course to be accessible and the test to work and post to site database and to [login to view URL], all of which is currently functioning. Need all errors to be logged in database (not currently happening) and emailed to me at errors at [login to view URL] (not currently happening). Need a mockup of the relevant pages (including functioning menus), for full site, tablet and phone version, and after they are approved, 10% of the price will be released. Need site to be secured, logging in, error pages, database accessing, with error logging and email to errors at [login to view URL] (with EXTENSIVE documentation) after which another 25% will be released. Remainder, 65%, will be released when the final site is accepted and fully functional, including PayPal purchasing, course registration, course testing, and course posting to CEBroker.com.