Using Volumio on Pi 3 B+ for Internet via Wifi

I set up Volumio yesterday on a Pi and it works great.

However, the room I have it set up in has no Wifi and I can’t add WiFi to that room as the wife doesn’t want it in there. I control the Volumio via the app on my phone (so yeah, I know, using Wifi :laughing: ) but that means I can’t surf when using it as the phone tries to use the Wifi Internet rather than 3G. I can get around this using an Android application (Mobiwol for anyone interested) to route Chrome to 3G each time but that is a faff.

Is there a way to have Volumio also act as a bridge to my network?