okay first of all you need an interface, as you just said.
i would recommend you the
alesis io-2:
- two-track recording via usb (1 !) - that would mean that you can record from two sources/mics at the same time.
- 2 XLR mic inputs
with phantom power (for condensor mics) / 2 stereo line inputs
- ultra low-latency
if you want to record singing you need a pop-shield (you can simply make one with an old pair of nylons)
for the mic you have several options:
dynamic mic - 'normally' used for recording amps. you can go for a
shure 57 which would be the best solution.
condensor mic - either small or large diaphragm, best used for vocals. if you have a thin voice i'd recommend a large diaphragm mic because it makes your voice sound more big.
if condensor mics are too expensive for your budget, you can also go for a dynamic microphone for singing. maybe anyone else here can recommend any good ones.