user manual, pages 12-13:
Dual Display Configurations for the Onboard Graphics:
This motherboard provides three video output ports: D-Sub, DVI-D, and HDMI. Dual monitor confgurations
are supported in operating system environment only, but not during the BIOS Setup or POST process.
since you have the board, and probably two monitors available, try it out! i'm thinking you can use the onboard connectors (pick any two) to get video signals and have windows show as using dual screens.
if that completely fails in every combination, then look at a graphics card. which card? doesn't matter. for what you want, anything made in the last few years will be fine.