Yes, Cubase SE should suffice. But I've got no idea Cubase SE can be that cheap! However, since you already have Pro Audio 9, I believe you can upgrade to Sonar at a very good price.
I encountered similar problems as you since I'm now overseas. I've moved entirely to a mobile platform. The key is still your PC. Going overseas with a desktop is no joke - not to mention going through customs. So a notebook is your best choice.
What I got - Acer Aspire 1711 (2.8GHz, 1.25GB RAM). This is a desktop replacement and weighs 8kg. But it is really a desktop that looks like a notebook - everything inside is like a desktop (3.5" HD, desktop RAM etc). So it really functions as powerful and fast as a desktop. This thing is also upgradable - HD, RAM, and even the CPU can all be upgraded just like a desktop. It has a 17" screen.
I dual booted it - one for my daily work and one dedicated to music.
I also got Echo Indigo io for my soundcard and M-audio 1x1 midi interface. Everything goes under $3000. Of course, I already have my sequencer software and softsampler/samples long ago - so price does not include these.