If those links don't get ya what ya need, next focus on contact management tools related to
CRM (Customer Relations Management). There are an abundant amount of CRM tools out there to offer solutions for sales and contact management. I work with the government, many agencies deal with this kind of thing often enough.
Here is a page for CRM shareware solutions
Here is a page that allows you to specify your needs and it recommends professional CRM solutions merely so you can compare what you lose in open source or shareware tools.
The best web based CRM solution I've seen is
Sales Force. I would not call it small, though, but they have competitive pricing and one heck of a support and development community. Consider this as the company grows, not now.
-jim