Don't feel that the keywords with the highest search volumes are the ones that you must have. Rest assured, many of your competitors would have considered targeting these keywords too at some point.
The competition for these high volume words will be high, so you may find it better to target some of the lesser searched phrases which won't be getting as many competitors featuring against them.
Use tools such as Google Insights to see if there are keywords in your sector which your competitors are not utilising. Being in first position in the search rankings for a search term which achieves 1,000 searches a week may be better than being on the second page against a search term which generates 10,000 searches over the same period.
If you want to know more about Redweb Search, please drop an email to search@redweb.com or give us a call on 01202 779944.