With PR 6 you are sitting on a goldmine to be honest.
If you are looking to increase your traffic then I would advise a number of actions you can take:
1. Comment on relevant and popular blogs in your field (connected fields). If you do this enough ( spreading regular comments across maybe 10 different blogs ) then you will increase your traffic in the long run. Be warned that this isn't a quick fix solution though, more a steady build up of regular traffic.
2. As per TSO's advice, set up a blog if you can, and update it a couple of times a week (doesn't have to be more than 500-800 words a time, so shouldn't be too hard). This regular offering of fresh content, may not in itself bring in new traffic, but it will certainly encourage recurring visits. You can also have your friends and visitors digg or stumble your articles (with little buttons under each article linking to digg.com and stumbleupon.com ... if you used wordpress to set up your blog, then there are plugins that would do all of this for you). This will encourage lots of traffic if done correctly.
3. Link exchanges. To be honest I think this will be one of your best methods of bringing in new traffic, but it does rather mean sacrificing possible revenue. A lot of very popular websites would be more than happy to put a link on their webpages in exchange for a link on your webpage (in the footer, or sidecolumn etc ... ) as your domain is PR6. But, it does mean you can't sell the links, and I don't know if you were planning to.
4. Directory submission would work relatively well for you. Just google a list of good directories and sign your site up at the ones you find. This is labour intensive, but can work well.
5. If you have an ezine articles account, then you should put a link to your site in your resources box, and then either pay someone to write a series of short 3-600 word articles for you, or write them yourself. If you then submit them at ezinearticles, and a couple of other article directories, then you will bring in traffic.
6. Forum refferals are an under rated way of gaining traffic, and one that I really recommend. Find 2-3 big forums, perhaps like fws, or warriorforum.com etc... and contribute to the community. Then you can link to your site in your signature, and you will gain traffic.
Lastly, I would reccomend having someone look at SEO options for your website (search engine optimisation). They can review your keyword targeting, and keyword density etc ... and improve your search engine traffic no end.
Sorry
... got carried away. There are a load of other things you can do as well really. If you want, feel free to hit me up on msn and I can run you through a couple more
Cheers, and good luck