Building a website & Mobile App

I'm looking to create a new social networking and meetup group for people living with the HIV condition. I currently run the group on a website called [login to view URL] and looking to move this to a private domain I've done lots of requirements gathering and have been working with someone who helped me create a logo and brief idea, look and feel of what the website would look like. Initially looking for someone who can advise and guide me through setting up the website, someone who will take my idea, work with me to perfect my idea then build website and mobile app. Very much interested in hearing from people who can also guide me through security and how I would make the website very secure. Initially looking to go live with just a couple of pages but looking for a long term partner that I can work with for future enhancements / new features & pages