Need Google PR? You must build interesting and fresh content, of course it have useful information. Be consistent to update your site. Wait and see... Soon you will get what you want.
just provide usefull content on your site, more usefull content on your site, more people will recommended your site on their blogs/sites.
You work on niche related blogs and forum also work on social bookmarking websites, web 2.0, guest blogging and share on social network. If you will follow these techniques your Page Rank will be boost when Google update it.
You should get high PR links connected with your website. Even depends on the amount of traffic and the bounce rate on your website. The calculations can boost your website's Page rank.
Page rank of the website depends on quality content as well as both quality and quantity of backlinks. I hope you have been getting quality backlinks. If not, then start to do the same because quality is also most important factor to increase page rank of the website.