I would work on unique quality content aka on page soe. That makes it easier for off pag seo. But i would concentrate on traffic instead of pr. I myself would reather have a pr 2 with 10 uniques a day then a pr 6 with 500 but that is me.
Google has not updated its toolbar PR since January 19/20 2011, so I think you can rest assured waiting the next update. Also, the toolbar PR is just a rough estimate of the real PR, which is used by Google to rank the pages on the SERPs. So you should check your positions in the search result pages for your keywords - those talk more about the current importance of your site to Google than the outdated toolbar PR.
Concentrate on the quality of the content of your site. Write articles which are useful and easy to read and also interesting. Make sure your article is unique and original. All articles should be error free. Then concentrate about the quality of backlinks. Make backlinks with dofollow, high PR sites which are in the same niche of your site. Hope you will get PR doing this.
IMO you shouldn't worry about PR if you have lots of visitors and your keyword ranks good in Google's SERP. All newer sites will have this handicap until the next PR update and nothing is going to happen until then. So keep building quality links and be patient.
Post high quality content and get relevant theme based back links to your website. it will really effect PR of your website.
just share my experience you must search link partners for your website with Pagerank 1 or above and then be patient, after several months your pagerank will be increase