USB is ALWAYS 5V, and correct Amps supply would be 1A, though actual usage varies from unit to unit - this apparently only need 0.5A.
Keep in mind that just because this is the correct voltage for the USB plug, the power socket may need a completely different voltage. I would look at the voltage stated (below?) the actual DC input on the unit, this will also reveal the correct polarity with a small symbol. In some cases a range of voltages will all suffice, since some units (mind you i have no idea if this is the case here) will be able to adjust to use any current with the provided range.
Best of luck.