Then my recomendation above holds
Low Budget but good:
M-Audio Fast Track Pro
fast PC with 2GB Memory and a big HDD or 2
will get you started
A midi keyboard just for composing is not a big deal. You can probably pick something used for real CHEAP (if you buy Cubase and the keyboard from a music store, you will probably have someone that you can ask questions too! A big advantage in the miuddle of the lerning curve!)..
You will want to invest in some good midi instrument plug ins, but that depends on what you are scoring for