How Can I get the best quality home recording?

My band is recording an EP in the next two weeks and we've chosen to
do it at home because we have relatively good gear and don't have the
cash to go into studio just yet. I've basically got a PC devoted
entirely to recordign with Cubase software. The soundcard device I've
got is a Tascam US-122L. I also have a Digitech mixing desk incase I
need it. The only issue is a good condenser mic (would be used for
vocals/acoustic guitar), but we're just going to rent a good quality
one.

What would be the best way to use all this gear? Should I run directly
out of my guitar pedal into the Tascam, or through an Amp? I have
often found the sound changes quite significantly between the amp and
the computer. As for vocals, would I run the mic directly into the
tascam (it has Phantom Power), or should I run it through the mixing
desk first? Any other help would be appreciated! thanks