You sure have distinct group circles in life. While one must be your inner circle, the other is your outer one. Inner circle comprises of friends, family and colleagues while the outer circle comprises of distant relatives, old friends, ex-colleagues, and others.
Initially you need to reach out to your inner circle that is sure to support you. They know how passionate you are about the cause and hence are bound to support. When the outer circle sees that you have support from the inner circle, they are also going to extend their support. Expand your network and reach out to anyone and everyone you know.