Hello,
You wrote something you need a soundcard, have you got that soundcard you wanted for recording acoustic guitar and voice? If you are still looking for it, I have two recomandations for you: m-audio Fast Track Pro, and Focusrite Saffire USB 6 - I have this oane, and it is brilliant! It record very well acoustic guitar, has even balanced IN, and even instrument in, an two autputs, plus headphones out, and I am using it for recording as well as for DJ-ing, has metall cover, it is really well designed, has phantom power for condenser microphones... and USB conector, without any cabel for power supply. Hope you choose the best sound card for you! Cheers!