Best mixer and/or preamp for a Shure SM7B mic?

Pilot X-Phile · **Voice Talent** Joined: 06 Mar 2007 Posts: 1

I am very new at this.
I need to record voiceovers on my pc (P4, 3.2Ghz, 2GB RAM, 350GB HD, WinXP Home)
I use Sony Soundforge 8.0 and Adobe Audition 2.0. and have a Creative Sound Blaster X-Fi Fatal1ty Extreme Gamer sound card.
I just got a Shure SM7B mic, but since it has very, very low output I'm not sure if I should get a mixer w/ preamps, or a mic preamp, or both.
I tried a Yamaha MW10 USB mixer but the output was not high enough. I changed it for a Line 6 Toneport UX2 USB Recording/modeling interface and it worked better because of its preamps and real time special fx, but it has limited channels for mixing. Now I have an Edirol UA-25 USB and the output is as low as with the Yamaha and besides It can't mix. I was thinking of going back to the Toneport, but someone told me that USB interfaces were not good for voice-overs and I should get a mixer and/or preamp which connects to my sound card.
What would be the best to do? Thanks in advance.