Diving Holidays Portal

I need a good technical person who is fluent in PHP scripting and MySQL database creation and the interlinking operations of both. I have a website advertising portal that has advertising subscription plans. When a new advertiser joins they sign-up on a PHP form and selects a advertising plan. On submission this information passes to the database and creates a new Advertising Agent. The next process passes the captured plan through a PayPal gateway to complete the payment process. This is working fine. There are two administration consoles, one for the advertiser to manage their campaigns and one for the site administrator to manage the advertiser and listings. This is currently live with a single 12 month subscription plan. This is the oart that needs changing. I need someone to modify the PHP script and MySQL database so that the prospective advertiser can select either 3, 6 or 12 month advertising plans instead of the current 12 month only plan. Plus I need to be able to monitor expiry dates and manually add or change dates as need be in the admin console. My current supplier who designed the system has taken on so much work he is unable to support me anymore which is not acceptable to me. The person applying for this work needs to be available as a support person as an when required. The project is new so its still going through teething problems and I cant be let down because my PHP/MySQL Techy is busy with 'new' customers. Only dedicated professionals need appply.