There's no Silver Bullet software that will automagically increase your search engine rankings. If anyone tells you different, they're probably trying to sell you something. However, there are some great tools that can help you analyze your pages and monitor performance, but hey, you're already an expert with Google Webmaster Tools, right?
Follow the excellent advice on Google's own pages and your site will be seen by people who are interested in your stuff. If you try to 'trick' your way up the page and Google find out, you will suffer. Also, be careful if you do decide to buy SEO services from one of the many people claiming to be able to help you: There's nothing to stop them using 'illegal' techniques - it will get results, but they expose your business to the risk that Google could remove you from their index. That would be disastrous for most businesses. Make sure you know what your SEO people are really doing with your web site.
You can check your pages with a few tools listed below.
Get your keyword density right:
http://www.ranks.nl/tools/spider.html
But not too much:
http://tool.motoricerca.info/spam-detector/
Are your keywords meaningful?
http://www.w3.org/2003/12/semantic-extractor.html
These are supposed to be good but we've not tried them:
http://raven-seo-tools.com/
and, of course, the grand-daddy of them all:
http://www.google.com/webmasters/
Comprehensive and very good:
http://buildingfindablewebsites.com/
Simple and lo-tech:
http://www.amazon.co.uk/dp/184078332X
Not quite SEO, but useful if you complement your SEO with Google Adwords:
http://www.amazon.co.uk/dp/190594098X
If it all looks too much like hard work or you just want someone to hold your hand, contact us for a friendly chat and we'll try to help.