Congratulations, Littlefox; you've got essentially a very good starter kit, provided by your family to see if you've got the bug and will take this to the next level. (You may want to post this again on the Home, Project Studios forum, or DAWs, etc.)
The mics you mention are indeed dynamic mics, and while they can certainly sound great for what you're doing, there are other types of mics (specficifally condenser and ribbons) that will give you different results. One could fill a book on all of this stuff, so you've got your work cut out for you. If you're at the stage of just finding out the differences between them all, then too much additional info will only confuse you right now. Plus, with a limited budget like you describe, I don't think you're at the point of making world-class recordings just yet, so it's a good time to learn everything you can about what you've got right now, and learn as you grow.
From what I read, you can only record two inputs (mics) at a time with that box, so there are a few limits to what you can do with it. You can't record stereo piano and vocal all at once, for example. Again, I still think it's a great way to get your feet wet with this stuff.
I don't see much else in that Fast Track package that's terribly exciting; it looks like there's a lot of guitar software "Stomp box" plug-in emulators, and a light version of Ableton 5.0? (I read this quickly and don't recall exactly what they've bundled it with...) It seems more like a loop-based sequencer/recorder, although I'm sure you can do some multitracking with it. Still, this is a good starter kit, and if you're truly bitten by the recording bug, I would suggest the next thing you buy is better recording software for your computer. (Don't know if you're Mac or PC, but there are good things for either platform.)
After that, perhaps a good entry level condenser mic for your vocals and other instruments. It's a buyers market out there, and even a few hundred bucks will get you some great sounding mics. (Studio Projects, MXL, ADK, etc.)
Hope you have a good time with the new goodies, and check back here for more info as you grow. You're at a great time in life: it's all ahead of you, and yours to learn, if you want it. 8-)