If you are supporting a specific, well-known organization, you should be able to get permission from that organization to use its logo on your materials, as well. You should also make an appointment to chat/meet with the local representative of that organization to discuss various ways you can work with the group (perhaps as a sponsor of the annual fund-raising gala). The organization might be willing to put your logo on its materials and a hyperlinked version of your logo on its website because you are an ongoing supporter.
I'd also suggest creating several special events over the course of a year. Hook up with other like-minded philanthropic entrepreneurs, promote yourselves and your mission in area newspapers and magazines (through PR), with the events being built around the concept of benefiting another local charity, such as a food bank or women's shelter.
Be creative and constantly communicate your involvement in this charitable mission with sensitivity. You'll be able to raise awareness, funds and build your brand and sales all in one fell swoop
Best of luck with your business!