How do I get the Mic to work with LOGITECH X-530 Speaker System (5.1)?

[souljah]

I have 5.1 speaker system which take up all three spots for wires on my soundcard. Now where do I put the MIC, there is no place left. Can anybody help me or if anybody who has this system LOGITECH X-530 Speaker System, help me that'll be great.