networking - Need help choosing a router and/or wireless AP for a 15-40 person office?

I've been tasked with improving the wireless network at my
office / co-working space. I'm not particularly experienced with business network
infrastructure, but I'm more experienced than probably all of the other people here and
have volunteered to figure it
out.

Our main issue is that our wifi
network is lacking. Typically we have around 30 wifi devices in the office at a time,
half of which are phones and half of which are laptops, but sometimes it can go as high
as 60 - 80 devices. For example, we were a jam site for the last global game jam and had
40 laptops vying for wifi bandwidth, and some untold number of mobile
devices.

Most of these laptops are running
software like Dropbox or Google Drive, which sucks up a lot of bandwidth. Occasionally
people may be streaming video and audio. We also regularly do video conference calls
over wifi, and sometimes they don't perform well, which is the biggest thorn in people's
sides.

We have the budget to get ourselves
decent networking hardware, but I'm not sure what will fulfill our needs given the
above. I'm planning on having our modem, router, switches, and wireless AP be separate
devices since that generally seems to be recommend
here.

Past that, I'm not sure how to move
forward! In particular, I'm not sure how to choose a router, wireless AP / router, or
both that will work for us. Other questions I'm looking for help on include but are not
limited
to:

• Will
  QoS help us prioritize important traffic like video calls and web traffic over bandwidth
  suckers like Dropbox or BitTorrent? If so, should QoS happen at the router, the wireless
  AP, or both?




• Do we actually want the
  wireless AP to be a separate piece of hardware from the
  router?




• Could we get a consumer level
  wifi router and put it in bridge mode? Or is it better to get a business level access
  point?




• Should we just hire someone
  else to handle
  this?

Any help
will be greatly appreciated!