A/V over ip

I have been tasked to create an a/v system for a church. I can do all the a/v stuff, but I would like to bounce a network idea off of people that would know more than me. I need to send video all over the church. There is an existing cat6 wire from the network switch. I have not seen this switch, but I can assume that it is probably not managed or possibly not even enterprise grade. I am worried about other traffic on the network. I was thinking of buying a small 10G switch and distributing video though that switch and connect the old switch to the uplink on the new switch because I will need internet on that side also. My thinking is that if all my equipment is on a separate switch if the other gets overloaded mine will still work. It will also keep my traffic off of the original switch. Connecting them together will allow me to have internet to some of my equipment that needs it.

I am not sure of bandwidth requirements from the A/V equipment as far a distribution goes (I have not picked out that equipment yet). The streaming computer will be sending out 5Mb/s over that same line and that is why the internet is needed on the second switch.

Thanks for the help the last time I worked in networking was 18 years ago.