Password Complexity Configuration

OK, Here goes:

I use the OS-X password generator for websites I visit to generate complex passwords; Some websites, however require the addition of numbers and special characters in their password submissions. While the password generator uses dashes "-" as their special character, it does not use numbers at all which causes me to make up some password to use which at times is a pain. I've heard that one can engage a terminal session to change this, I was wondering if someone could lend a hand here. I have had some experience with Unix/Linux in the past any help would be appreciated.

Bottom line: I would like to add more special characters and numbers to the password generator.

Thanks!