Answer:
Im not sure if every case works the same. But I do know that It will all depend on how did you enter the U.S
If you came ilegally, the process will take a long time ( we are talking about years)
but If not, it takes aproximately 3 or 4 months to get the papers that allow you to work and in another 2 or 3 months you should receive the documents that allow you to travel overseas (residency) I guess it will be call..