Help for a network project Conference Room

Hi guys,

I need some good suggestion to restructure a network editing in a conference room.

Currently the ADSL landline supports 10Mbps DL and 1Mbps UL.
The modem is a very simple Digicom CX connetted as bridge to a Dual-Band Wireless-N900 Gigabit Router ASUS RT-N66U.
There is also a 4G modem which can connect to a cell tower (200 meters far away) which guaranteed 70Mbps symmetrical. Given the high costs and data traffic per month (>10GB) the subscription has been temporarily suspended.

Requirements have increased over the time, and now the network needs to be upgraded.

- During weekly events there may be active Skype connections that allow remote users to follow the conference.

- It is also possible that a speaker want to show streaming video, presentations or other internet resources from its tablet through a video projection system .

- There are security cameras to be managed remotely.

- A restricted wifi access for mobile devices (eg. a guest network that can access only few web domain as www.nasa.gov or www.google.com) could be provided to all guest users (<100) in the conference room

- One or more full internet access as well as to the local network resources (computer, printer, clouding) must be provided to administrators

I was looking for some suggestions on how to roll out the project, which kind of products to purchase (even semi-professional), which of them can be re-used (if possibile) and where to intervene to strengthen the network.

Thank you for and help