Business Proposals, brochures and marketing materials

I am looking for someone to work with me on an ongoing basis to assist em in the preparation of proposals and marketing materials. They will need excellent english written skills (not necessarily spoken), ability to be creative in creating marketing materials, mainly using MS office. In addition they will need to be able to write to respond to IT bids, tenders and proposals. Access to someone who can also do and bring together good graphics and layout would be good. They will need to be able to take a concept and copy write content for my business websites and marketing materials and maintain them. There may be an ongoing requirement for updating social media sites based on my input. There is a long term opportunity jointly expand this as a business in offering this as a business service to my clients.