any other places that you can stay for a short period of time? Perhaps you can go down to HDB personally to ask about your application. Usually they give priority to small young families, especially if your child is still a baby. Of course you have to take into consideration other factors too such as if the current house is under your hubby's name, your total household income must not exceed the max requirement for house renting fm HDB etc.
If you want to walk away from your current life, take your child with you since your ILs are not treating him well. Sorry to say this but ya, its true right?