Sorry to also diss the website, but I have to agree with the above comments.
Cracking the commercial is a tough cookie, and the vast majority of letters and flyers will just end up in the recycle bin.
The best way of making new contacts is to make a nuisance of yourself (in the nicest possible way off course) and that is to cold sell. I have found that the best way of doing this is calling the company, and asking them how I can go about getting my company on there approved traders list.
Many will blank you straight away, but in some cases I have been advised to write and give copies of insurances to ...... This is a good start as you now have a name of a specific person within the organisation that deals with the likes of you.
Only last month I managed to secure 3 new contracts by this method. The only thing you must remember is not to get dejected, I have spent many a morning making numerous calls and obtained naff all. You must have a big chin, and be prepared to take the knocks. The problem is that a huge percentage of people do not like doing this, me included, but it was either that or my buisness folded.
Best of luck, and I hope this help a bit.