Advice On Cubase Sx, Hardware And My G5., Where does this go??? Options

[humphz]

Hi Everyone.
Where do I begin... I managed to get a copy of Cubase SX of a friend who is upgrading his whole set up. Its been a god send as I also have an emu audity 2000 sound module (shes a beauty). I have a mixer too that was knocking around the house and decided to try and attempt to link everything up. The mixing side of things has always baffled me and maybe I am going about things the wrong way>

A few questions:
• Do I need a soundcard for my G5, any suggestions what sorts, M-Audio, TerraTec...
• Is it worth trying to get the mixer up n running or maybe sell it and put the money to the things
I need. Its a Topaz S-Series S16-4 and its just been sitting around, only wired it up once.I was
thinking of selling it but cant imagine i'd get much for it.
• I was reading one of the topics on here and someone mentioned needing an extra harddrive. My
music is mainly midi with a few audio samples.

I treated myself last year to a new G5 but all my music making was all based around OS 9 when i use to use my imac so its all been gathering dust. Been jamming on Garageband to take away the frustration.

I want to base everything around my G5, Sound module and Cubase SX.

All feedback welcome.

Thanks for listening