I'd highly recommend getting the Royal Road book to supplement what you're learning from the DVDs. That way, you'll begin to get used to learning magic from books (a skill you'll definitely want to develop as you progress in magic) with the safety-net of the DVDs in case you feel that you need to see the techniques and tricks performed.
After you've got everything in Royal Road down, get Expert Card Technique by Jean Hugard and Frederick Braue (who also wrote Royal Road). Buy a third edition if you can find it, as it has a couple of extra chapters. Third editions in print are fairly scarce but I believe the eBook version sold by Lybrary.com is taken from the third edition, so has the extra content. You don't necessarily have to master everything out of Expert Card Technique but you'll find a lot of good material in there and it'll definitely open your eyes to what's possible with cards and give you ideas about where you want to take your magic.
Then, get The Expert at the Card Table by S W Erdnase. I don't think there is a single card magician (who's worthy of the name) who doesn't count this as one of the most important books in the history of card work. It's not exactly easy, but once you start to get to grips with the sleights, tricks and, more importantly, the thinking and subtleties described by Erdnase, you'll be very glad you did.
After you're familiar with the material out of these three books you won't be a beginner any more, and you won't need anyone's advice about where to go next.
