Keep the switch and add a dedicated Access Point in your office to give you a new strong source of WiFi in that area. The Access Point I recommend for such scenarios s the Ubiquiti U6 Lite or Pro.
You can also use any off-the-shelf, all-in-one router like an ASUS or Netgear to do the same thing. Just put this router into "Access Point Mode" according to its manual. You can either just attach it to your current switch, or use the router's 4 built in LAN ports as a switch and then use your existing switch elsewhere.