Website developer to improve, secure and make existing website mobile friendly

General information for the website: This is an artist webpage with news, gallery and general information.
Kind of development: Customization of existing website
Num. of web pages/modules: 6
Description of every page/module: The website has 6 pages. Index(home), about, news, exhibitions, gallery, contact.
Description of requirements/features: Immediate Changes: (by 14 September)
-The website must be optimised and customised to become fully responsive and mobile-friendly and fulfil Google's webmaster guidelines in terms of design, speed, performance, SEO and other aspects in relation to both iOS and Android devices.

Future Changes: (by 30 September)
-Come up with solutions of facilitating easy day-to-day update and upload of news, like the inclusion of a CMS/blog, database etc.
-Give advice and Make all necessary changes to minimise hits from bots, spam and other security threats.
-Customise settings on google analytics, hosting on Gandi and DNS on Cloudflare to get more reliable data and rectify security issues.
Extra services needed: Customization, Optimization, Security
Extra notes: