Singapore is a Rule of Law nation.
Thru immediate medical records, along with written tenancy records & critically video evidences of the criminals involved, it would be sufficient to seek Justice Served in our Courts,
Do not, DO NOT, ask for more evidences such as witnesses, worse to pay them, as there WILL be many whom saw nothing but only out for financial gain, & will be easily TORN APART by the defendants lawyers in Court, bringing only doubts to the Judges whereby justice can only be served beyond reasonable doubts..
All the best to the victim & may she see a speedy recovery. No matter what had been done, there is NO need to resort to violence. The ones who do so will ALWAYS be on the losing end in our Rule of law Nation.