Any advice for foster parents?

I was wondering if any one had any suggestions as to what would be a effective way get through to a 21 mth old? We have a foster daughter who has behavioral issues and time out just isn;t working. We don't her or do any kind of physical punishment, but timeout just doesnt seem to work.. She throws things, throws tantrums tells you no all the time etc.. She has thrown items and has hit my 10 mth old etc and We are trying to figure out how to help her but nothing is seeming to work.. Any Suggestions greatly appreciated.