Try compressing less after going though the audio signal path and cleaning that up.

The idea is to even the vocal dynamics a bit so they sit well in the mix. If you squash it until the noise floor level of that track is too loud then your probally compressing too much. try and find a setting that helps the vocal sit well in the mix and keeps the noise floor from being annoying.

Also try a band pass compressor as well. Considering your card and mic, there are probally a few hot spots and the rest is probally OK or at least workable. Compress only what isn't working for you and leave the rest alone.