Have you tried going to :
"Windows Control Panel" -> "Sound" (to the right, there's a menu for "Related Settings") -> choose "Sound Control Panel" -> swtich to the "Recording" tab -> Choose the USB microphone you have and click "Properties" -> go to "Levels" tab.
That's where microphone boost is found.
Unfortunately I'm not sure when it comes to Enhancements, but I believe additional software is required for that.
-Is there no software available for the USB microphone you have?
Usually that's what provides options for audio settings (EQ, echo cancellation, niose reduction etc...).
You can't connect a USB microphone to another sound card.
Any USB sound device, both sound cards, microphones and headsets, has their own sound processor built-in, so they function as their own individual device.
When you connect a USB headset or a USB microphone to your PC, it doesn't communicate with the onboard sound card, it acts as a sound card on its own. That's why you can't find any dedicated sound cards with USB input.
So if you bought a new sound card, you'd still not be able to control the USB microphone you currently have, using the software for the new sound card (unless the manufacturer has added support for other devices in their software, which I don't think I've ever come across before, but some might support it).