You should try and get a scholarship from an external grantor such as a private or public research foundation.
Your supervisor will know how to do and will know of foundations in your research field, which you can apply to.
Read the fine print!
Be careful to read through and comply with the grantor’s conditions for giving you the scholarship. Some grantors do not allow the grantee to participate actively in a master’s programme while using the grant.
If you are granted a 12-month scholarship from a grantor under these conditions you must contact the Graduate School in order to find a solution that ensures you comply with the grant conditions.