[Jomi]

Tomg123,
I'm not an expert on recording but I can tell you that my preamp connects to the line-in and there are no other connections to the pc. The mic OR guitar can then be plugged into the preamp.
The preamp instructions say it's best not to connect BOTH the mic and guitar at the same time as one will tend to attenuate (opposite of amplify) the other.

I use adobe auditions (pc software) for mixing instead of hardware.

Your $30 condensor mic could well be all you need once you connect it via a preamp. (or mixer with built in preamp)

hope this helps,

John