If I were a billionaire I'd start a non-profit organisation. I would go into Africa and safer parts of the middle east.
My organisation would create safe havens for abused and neglected children and women.
I would build about twenty resort style facilities each would house about 300 orphans, I would build a perimeter wall and staff the facility with gaurds so that child soldiers and such could come to the facilities for safety. The facilities would include things like swimming pool's cafeteria's and air conditioning. As well as a school to teach the children skills. Due to financial costs I would only open about twenty such facilities. These facilities would be maintained by donations to my organisation and future facilities built by donor dollars.
I would also build about five or six similiar facilities in Middle Eastern and European countries where Sex slavery is huge. These facilities would be big, house up to 500. Unlike the other facilities these would not have pools and a gym and a school. They would be primarily living courters. Protected by armed gaurds with a blast wall surrounding them. Inside their would be a store for food and a councilling facility to council women. The primary goal of the facility would be to find the women safe countries to go to. Hopefully women could go back to their home countries if they were kidnapped and such. Their would also be high risk volunteers who would scour the cities for sex slaves and help get them into this facility.
Right now a primary problem with helping child soldiers and sex slaves is the lack of a safe place for them to live. Child soldiers are often forced at gun point to return to camp's, missionaries are unable to save many and if they do they are constantly fearing for their lives. In the same way sex slaves who get free also fear for their lives, they don't have a safe place to go. I heard last year of a women's shelter staffed by missionaries that got bombed.
What they need are safe facilities. Which I would provide. Protected by blast walls, survielence systems and armed guards. These facilities would be safe haven's for children and women who fear for their lives and have been abused. Also incase your wondering I would build these facilities with Government permission, so if attacked the armed gaurds could hold off the assailents till Government troops (In the case of child soldiers) or Police (In the case of sex slaves) could arrive to provide further security!