AS level Business studies 2016 (Edexcel)Watch
As for websites, you can check these out:
- http://www.dineshbakshi.com/as-a-level-business-studies (this is for the Cambridge board, but you could find it useful)
- http://www.tutor2u.net/business/reference (tutor2u is always a helpful resource)
When it comes to AS level business, I feel like you don't need to stress too much about it. Units 1 and 2 should be familiar to you as they're really just more detailed lessons of what you've already studied for you IGCSEs. Usually, I find that the textbook is more than enough. You could try making your own revision guide by going through your book and the syllabus and then revising that just before your exam.
If you need anymore help, feel free to ask!