hello, i'm looking to get a basic system set-up on my laptop.

I have a 1 GHZ G4 Powerbook, 512 MB Memory, 60 GB Hard Drive. i'm leaning towards using Nuendo because i have a basic knowledge of it already. I will only be using this for personal purposes, to demo song ideas. I won't need more than two inputs at a time, not looking to get to complicated, just want to be able to plug in and record some tracks and make quick mixdowns to listen back to. I need whatever I have to be very mobile, to take on the road.
my main questions are:

- is my MAC ready/capable of handling this sort of thing?
- What sound card/interface do i need to work with Nuendo?
- are Nuendo files transferable from a MAC system to a PC?

any other insite/advice is greatly appreciated. THANKS in advance.

- gi