Hello Ashley, welcome to PCHF.
I'm afraid you can only play through a single output source at any one time. The output source is selected within
Control Panel, Sound and Audio Devices, Audio tab. Some applications also allow you to select a default audio device, but cannot play to three devices at the same time, no application is designed to work that way.
Your best bet, if you already have a sound card to to purchase something like this to be used in addition to your usb speakers, or for standard audio speakers:
Boostaroo 3-way Splitter W/ USB Ac, T794, Boostaroo at Cyberguys.com
EDIT: Marked as Answered.