It was going well till you said the USB bit - you need a USB mic with gain settings, or attenuators. Recording trumpet and piano together will be a real challenge. You will be doing lots of moving a single mic around. I assume a mono recording is the aim? Ideally you would record with two mics as a minimum - and often 3, using two on the piano, or a stereo pair at more of a distance in a nice sounding space. A typical podcasting mic, connected via USB will be a challenge for blend and balance, although in a nice space, once you find the right place, it will be usable - and maybe you could add some gentle reverb to give it a sense of space with width.
What are you trying to do? The USB bit means compromise, I'm afraid.