PR and DA depend on your site popularity, quality, regular update etc.. So you have to do quality link building progressively, at the same time you have to create fresh content for better result!
DA is Domain Authority. The number of root domains which link to different pages on your website rather than getting all links pointing directly to your website.
DA(domain authority ) is like moz.org like rank by moz.com, almost like google PR(page rank) . Moz have 150+ calculating metric for the DA. You can learm more http://moz.com/learn/seo/domain-authority
I've been doing tons of domain research lately as I build my private network of high PR sites. Honestly blogroll links from a website who's homepage has a higher PageRank than yours can boost your PageRank a lot.