Which would suit my needs best: iPad or Macbook?

I have a Toshiba laptop, and my mom has a Macbook Pro. So, I'm stuck on a Windows machine, but I've had a taste of what Mac can do. I want to switch over to Apple.

But do I really need to go whole hog and get a Mac, or will an iPad do the trick? (If I get an iPad, I'll keep my PC for certain programs.)

Here's what I'll need the Mac/iPad for:

-Recording music with GarageBand (I need good quality recording, like I've heard from Mac's built in mic - will I get that with iPad? I've heard there's a separate mic called iRig, does that give a better quality recording than iPad's built in mic?)

-Writing papers for my college courses, and

-writing my novel (especially during national novel writing month, aka nanowrimo)

-Surfing the web, listening to music, watching video, other standard stuff.

So what do you think? Will an iPad satisfy me, or should I save up for a Mac? Another concern is cost - I'm also trying to save for a new guitar, which should be just under $400, so if I *can* spend less on electronics, that's great.

Thanks so much y'all :)