PR is not the most important seo tactic. Backlinks are. PR is a measure of backlinks. That's like saying you need to increase how long your ruler measures your mouse. It's not logical. The best thing for SEO and PR is links. Get links.
you DONT!!! I repeat DONT need backlinks to rank well in search engines. My website allthingsps3.info bearly has 100 links (according to yahoo) and was ranking 2-3 in google for many keywords relating to 'upcoming ps3 dates'. about 100 terms in total show up for my traffic sources. This site had no promotion (except SE submission and a couple diggs) and was ranking this high. So I think this proves that you dont need the backlinks. Oh and these terms showed millions of results