How do you politely ask your biyenan to move out of your house?

I would agree with Mikaela. It would be more polite if your spouse will be the one to talk to her mom. Usually in cases like this, my older friends suggest that it should be the son/daughter of the in-law who is responsible in explaining that they need some time to talk things over and fix some issues within the family. Expect a negative reaction but that's normal most of the time.