I need to know what the hose at the bottom of the radiator is called that leads to overflow?

The Radiator hose at the bottom of the radiator is missing and it pours water when I put water into from the bottom where the hose is and it keeps running red hot every few mins? Afraid it will cause my motor to lock up on me? What Should I do about it? Also my transmission has a small leak from the bottom pan and wondering if it is gasket problem? And I have a plug that comes from the oil pan that has broken and is spraying oil all over bottom of engine and parts. Can I buy another plug for this problem? How do long should it take to put on my front brakes?