There are a number of different terms used to describe the concept of community psychology or critical psychology. Some of the more frequently used terms you might want to try:
"community psychology"
"critical psychology"
"liberation psychology"
"radical psychology"
"critical social psychology"
"critical community psychology"
Another effective way to search is to search for works by the major authors in the field.
"Fox, Dennis"
"Friere, Paolo"
"Prilleltensky, Isaac"
"Hook, Derek"
"Parker, Ian"
"Martín-Baró, Ignacio"
"Burton, Mark"