Another way to increase visibility is to do joint ventures with the non-profit. Consider having your employees do things like a walk-a-thon to benefit your charity. Your company can give away products and services to your charity of choice, along with donating money. Or alternatively, offer a matching program for charitable donations. Not only does this increase your visibility with your clients, there is a possibility that you can use these charitable contributions to gain much needed PR for your company, therefore getting your name out there amongst potential new clients.
Have you had an employee that has gone through cancer? Perhaps make the cause personal to your company by supporting that employee in his or her walk for cancer, as well as any other employees that join him or her.
The bottom line is that having a strong philanthropic strategy is not only good for business but is beneficial to the cause that you choose. Choose your cause carefully, make sure that your employees are on board and informed and educate your potential clients about what your company is doing to give back. In the long run, everyone (your company, your employees, the cause and the client) will win.