Ongoing Website Maintenance - Expert Joomla/PHP required

I need an PHP/MySQL expert with Joomla knowledge to test and correct issues that arise on my joomla web site. I will need an initial tuning of the site to address current issues, but I need to retain your services to deal with maintenance issues that occur on my website from time to time. Site Components Joomla CMS Amember Membership Component/Payment processor JROX - JAM (Affiliate Manager) Current issues that need addressing: 1. Cloned version of site using Component (Multi Sites) not functioning as specified. When member moves from the main site domain to subdomain the user login status must be retained. However, when a user moves from main domain to subdomain back to main domain they must log in to each site separately. 2. Ensure components are tied together properly (Joomla - Amember - JAM). There are 5 commission levels for the Gold Membership, with various payouts. It is critical that affiliate linage is maintained and payments propery credited to the referring affiliate. There are currently 2 membership levels (Gold & Silver). When a user joins as a Gold member, they are processed via Amember and payment is made through PayPal. Once payment is completed, the new Gold member is automatically placed into the affiliate program (JAM). If they were referred by another Gold member, the member that referred them gets credited a commission. There are 5 commission levels, with various payouts.