Sorry to hear about your computer!
And great questions - Veritas Prep actually has a new iPad app that includes all of the Veritas Prep on Demand video lessons formatted specifically for mobile devices (it works on iPhone, too), so you'll certainly be able to view those lessons. The limitation to the iPad, at least for GMAT study, however is that the CAT practice tests won't run on iPad, so you'd need to find a public computer in order to take those. And for the Live Online lessons - there's nothing inherent in the Java program that won't run on iPad, but our IT guys ultimately don't think that the iPad has enough processing power to keep up with a 3-hour multimedia show, so it's not advisable to plan on the iPad for Live Online just yet...
As for a Mac, everything but the official GMATPrep practice tests will run on a Mac, and even those tests will be Mac-compatible by early 2012. I use my Macbook to teach the Live Online classes and I love it, so I can fully endorse Mac technology for GMAT study!