Joomla expert required for module extensions and SEO

I need an experienced joomla expert to work on an existing website. The job would involve:
(1) optimising the current web pages, meta tags/data, parameter settings etc to ensure that the information is fully optimised for search engines. We already appear on page 1 of google on certain keywords, however our percentage of search engine related clicks is low and can be better.
(2) Incorporating an online subscription module that enables users to pay a yearly, 3-yearly or one-off fee for downloading some of our material.
(3) Updating our paypal email templates and payment instructions to make the information more user friendly and easy to follow for customers (minor changes)
(4) Incorporating an affiliate system like idevaffilliate or something similar to enable the promotion of our products via affiliates.

We really need someone who is very experienced with a track record of having delivered similar work, who is deadline driven, professional, and willing to do the work for a realistic price.