Well, I would say better not to wonder about it much rather than keep the good work up your page rank will automatically jump once the next update occurs. Other than this you can try linking your site to high PR sites.... let us just not talk about it !
Keystoke, in an earlier post you've stated you are a link seller. If you have fallen foul of Google's policy on link schemes you are going to find it extraordinarily difficult to get page rank with them again.
You can increase your website's PR by doing the following activities such as:
1. Frequent updation of content in the website
2. Keyword used for searching your website should be more valuable
3. The content updated in your website should be related to the theme of your website.
4. More Number of useful backlinks should be created for your website in the social websites which are all having the high PR.
By doing the above things regularly you can get your website high PR in a short priod of time.