I agree, I was going to suggest DBT self-help books, some can be a bit overwhelming but worth a look even if you only do some parts. What part about BPD are you struggling with the most? It might also be a good idea to do some mindfulness exercises (mindfulness is part of DBT) and there are some excellent self-help books for that, too.
This one has some DBT exercises in it
http://www.thenile.com.au/books/Matt...9781572245136/
(but if you're looking to buy i think it is cheaper
here).
I actually have this book, I stupidly bought the large text version so it's a giant pain to read so I haven't read it much!
Maybe reading inspirational stories would be good for you too, in regards to your motivation?