For creating your music, the first thing I am going to recommend is of course FL Studio. I mean, it's really nice, and as flexible as you would need it to be. It comes pre-loaded with all kinds of sample instruments and getting more is as simple as loading a VST.
Now to answer the broader question here. "I have an idea for music, but I don't know how to make it happen" there is a growing market with a (currently limited, but growing) selection of tools.
First off UJAM. It's insanely fun to play with, and with the proper work it can make some really decent tracks. It's as simple to use as singing or humming the tune that you want. From there you can convert it into a variety of instruments* and use a number of (last I check) growing effects to mix and 'master' the track.
Then, if you have one, I recommend looking at Garage Band on the iPad. While not as full featured as it's sibling. It definitely makes creating music quickly a priority. It has a variety of smart instruments that can be used to quickly put together a track with limited effort. And if you check the link, it has drum kit's built in that just might solve your current issue (I was able to get rim shots out of it, and I think there is minor tonal differences when you strike in different locations).
There are no doubt more, but those three together let me put together all of my proto-music for all the prototypes that I work on.