To get traffic from search engines, you have to target a keywords which has enough searches per day. Also some long tail keywords have to be targeted at the same time to get more. To do that you have to do proper keyword research to analyze the competition for the keyword. Then you have to build backlinks to get higher search engine ranking position for that keyword.
If you really need traffic immediately, you can advertising using Google Adwords. There is also paid advertising from Yahoo Sponsored Search, Facebook, Paid Directories etc. As many folks have mentioned, PR does not automatically equate to many visitors.
yes it needs optimising. my web has pr 2 almost without doing nothing, only have similar names with popular sites
No matter how good your PR is, but it does matter if your keyword is ranking on top 10 and the amount of traffic your keyword can generate. Focus on niche rich keywords and try to rank them to get good traffic. PR alone is not enough.
If at this point you are not getting the traffic, that means you have to get your links spread all over the web. Obviously your niche is vast, so keep on looking for good important keywords. Bookmar your articles in as many bookmarking sites as you can. Be a regular commentator on forums like DP and on high ranked blogs of your niche. Infact I would say just make the net as your friend and increase your friends over the net, I am sure you will get the result preety soon