No one should try and provide psychological support to clients if they are not trained. Empathy, listening and peer support are important aspects to your work, however there will be times when professional psychological attention should be sought.
You should make contact with psychologists and psychology schools in order to build up a directory of competent, pro-bono mental health professionals experienced in trauma to whom you can refer clients in need of attention. You may approach child specialists, crisis specialists, or general practitioners. Place advertisements on local nonprofit or mental health fora, including universities.
Remember that it is important for your team to have access to psychological support as well, so you may wish to establish referral protocols for both clients and advocates.
It is also important that any psychologists to whom you decide to refer clients are well aware of the cultural differences between their treatment models and the potentially different world-views and healing preferences of clients from different backgrounds. Psychological attention must be culturally sensitive.