I'm going from info on your other post. It's not completely clear what you are trying to do using both the amp and the interface. But you want to use your interface instead of the sound card. (Essentially the interface is a replacement for the sound card.) If you want both the instrument and mic channels from the amp, you want to use the tape out channels rather than the direct out (which has only the instrument channel.)

Your right, sorry, I did not give my gear...though it is in my profile.

Edit Value
Mic: MXL 992
Preamp: Tube MP Project Series
Amp: Behringer Ultraacoustic ACX1000
MIDI Interface: M-Audio MIDISport 1x1
MIDI: Yamaha PSR-275

Computer: AMD 3.0Ghz Quad-Core, 4GB RAM
Sound Card: Realtek ALC888 (onboard)
OS: Windowns XP sp3
Program Cakewalk Sonar 8.5

My interface I do not think can be used in place of my sound card as it is a MIDI interface that I use to connect my keyboard to the computer is all. It only has a MIDI In and Out plus the USB port. The Amp I was planning on using for my mic, guitar, and base.

Your right, sorry, I did not give my gear...though it is in my profile.

Edit Value
Mic: MXL 992
Preamp: Tube MP Project Series
Amp: Behringer Ultraacoustic ACX1000
MIDI Interface: M-Audio MIDISport 1x1
MIDI: Yamaha PSR-275

Computer: AMD 3.0Ghz Quad-Core, 4GB RAM
Sound Card: Realtek ALC888 (onboard)
OS: Windowns XP sp3
Program Cakewalk Sonar 8.5

My interface I do not think can be used in place of my sound card as it is a MIDI interface that I use to connect my keyboard to the computer is all. It only has a MIDI In and Out plus the USB port. The Amp I was planning on using for my mic, guitar, and base.

So your plan is to use the computer soundcard to convert the analog output of the amp into a digital signal for the computer. I think that will work (with a dual 1/4" from the tape out to 1/8" stereo line in to the soundcard) but the quality won't be very good. The usual recommendation would be to use an analog to digital audio interface. If any of your gear is returnable you might want to try to describe exactly what you are trying to accomplish. Your gear seems to be purchased for a combination of live performance and recording. It might make sense, but it's not what I would recommend if your primary interest is multitrack recording.

Oh, and are you playing bass through that amp? Is it open back? (Can you see the speaker?)

I was thinking about returning the preamp because I did not realize that the amp had phantom power when I got it. So I will looking to what my options are for a Digital audio interface can get that. Once I have that I would not need to upgrade my sound card?

EDIT: So I was thinking about this...

http://pro-audio.musiciansfriend.com/product/MAudio-MobilePre-USB-Portable-Audio-Interface?sku=701368

I know it is cheap but I live in Hawaii so my budget is tight and I spent most of it on the computer and a new guitar...lol. Anyway that will work for what I need right?

Mic (guitar or bass) to Amp
Amp to Digital Audio Interface
Interface to Computer

Keyboard to Midi Interface
Midi Interface to Computer

Interfaces typically connect via USB or firewire to the PC, and your soundcard vanishes into thin air because you don't need it anymore (for input at least).