doing it right is more important than the quantity of work.. all the things above you have discribed above are almost perfect..

Install wordpress blog inside your website
write useful content for the user
tips tricks
use pingomatic
pingbacks
and thats it.. you are good to go

Yes i agree with Biggig that you have to be patient while you are doing SEO.. Do not get distracted because it requires time.. Just keep on following the basics!

Create social groups and add your links there

you did a great stuff because your site PR is 5. Most of the backlink technique you already used.
My view to create more backlink..

Article Submission,
press Release Submission,
Forum posting,
Comment on Related Blog,
Write content for different popular blog,
Profile link from web2.0
you can create link wheal

you can share how your site PR is 5. What you did for your site?

thanks