please help!!

i bought a Samson Studio GT pro bundle - includes usb monitors, and samson co1 mic.

i set everything u and it seemed to be working properly but for some reason, i can only hear myself on the mic, i cant actually record any vocals.

this is my first mac so plz be gentle w the instructions.

ive checked the sound settings in system preferences and in garage band with no luck, i seem to be having the same issue with logic.

maybe i didnt lug something in correctly... even though the only thing that actually plugs into the mac is the usb cable for the monitor, everything else is build directly into the monitor [mic plugs into the front of speakers]

i dont know if im being confusing or what, any help ANYONE could give would be awesome.