Get some nice flat response near field monitors. Don't try and mix on headphones unless you are quite experienced. Im not saying it can't be done it is just much more difficult using headphones. Similarly the computer speakers like stereo speakers color the sound. Not good for mixing.

A reasonable large diaphragm mic and some sort of preamp with a channel strip that has a deesser and can supply phantom power is not a bad idea. It is even better if it can plug directly into your sound card or computer via something S/P DIF or fire wire / USB.

Best of luck