Advice on recording drums?

Ok, My friend and I are both musicians and have recently been talking about recording our ideas. He plays guitar/ some vocals. I play drums and do vocals. I am looking into getting a drum microphone kit (probably a 5-7 mic kit) so we can start recording drums. I know to record vocals and guitars there are interfaces like the M-Audio Fasttrack and recording software (We are planning on purchasing that) But what I am confused about is what do I need to plug all those drum microphones into so I can put the audio onto my computer and recording software. Cause there will be around 5-7 mics. I have an 8 channel Powered mixer, but we usually use that to play through the PA's, plug guitars into, plug a microphone into, etc. I don't know if that would be useful for drum recording or anything but what do I know, Im still a teenager trying to learn what I can and pursue a dream. So please any help from experienced people would be much appreciated. (Also consider we are teenagers and are on a sorta slim budget)