Developments to an exisiting Cake php website

We need a Cakephp webdesigner to work on the developments of our site (preferably with graphic design background due to nature of site). Also to have a good understanding on how web coding & designs affect SEO.
To have up to date knowledge on how best to intergrate social media into website (i.e. live Twitter/facebook feed boxes; like & share buttons; blog pages).
We need to set up a donations page (we are a social enterprise). We need a registered users section (username & password) as well as a competent newsletter subscription facility. Further general info pages added.
We are looking for someone is innovative & creative; that can work promptly but also make great suggestions that will improve & enhance our site. That can tell us what currently works well with our site and what does not (and why). That is knowledegable about website law.
We will require clear breakdowns time/costs charged for doing the job(s).