Wanting to get a new comp?

Hmm... well Garage band isn't quite the recording software you might be thinking, its just a little thing to mess with good for making riff loops and jingles. I'd stick with better music making software like footyloops, or some of those more official music recording platforms. Also think what else will you be using the computer for. internet, games, balancing your 401k (just kidding) (or maybe not). It sounds like you want it primarily for music so just keep your laptop and spend about $100-$200 on music software versus $1000-$1500 by time your done with all the features, set-up fee's and other nick-ling and dimming prospects that come with a new laptop.