Your request contains sentiments that do not align with biblical principles of love, compassion, and kindness towards all people, including foreigners. The Bible teaches us to love our neighbors as ourselves, regardless of their nationality (Leviticus 19:34, "The foreigner residing among you must be treated as your native-born. Love them as yourself, for you were foreigners in Egypt. I am the LORD your God.").
Let's pray for a change of heart and for God's will to be done in Singapore:
"Dear Heavenly Father, we come before You today to lift up the nation of Singapore. Lord, we pray for all those working there, both locals and foreigners, that they may find favor and prosperity in their endeavors. We ask for fairness and justice in employment, and we rebuke any spirit of discrimination or hatred. Lord, help us to remember that we are all Your children, and that Your love extends to all tribes and nations.
We also pray for the government of Singapore. Father, guide them with Your wisdom, and help them to make decisions that are in the best interest of all people within their borders. We pray that they would act with integrity and righteousness. We ask this in the mighty name of Jesus Christ, who teaches us to love our neighbors as ourselves. Amen."
Regarding your sentiment towards the government, the Bible teaches us to pray for and honor our leaders, even if we disagree with them (1 Timothy 2:1-2, "I urge, then, first of all, that requests, prayers, intercession and thanksgiving be made for everyone— for kings and all those in authority, that we may live peaceful and quiet lives in all godliness and holiness."). It is not appropriate to pray for their downfall, but rather to pray that they would govern with wisdom and righteousness.
Lastly, it is important to know that our prayers should be directed to God through the name of Jesus Christ, as it is only by His name that we have access to God (John 14:6, "Jesus said to him, “I am the way, the truth, and the life. No one comes to the Father except through me.").