1998 Dodge Intrepid Had Coolant Leak Water Pump Area Engine Ran Hot Checked

HAD A COOLANT LEAK LOOKS LIKE FROM WATER PUMP AREA...ENGINE NEVER RAN HOT...CHECKED OIL STICK AND LOOKS LIKE WATER AND OIL HAVE MIXED AND LOOKS LIKE MALTED MILK IN ENGINE....DOES THIS PUMP FAILURE CAUSE THIS TO HAPPEN...IF SO WHAT DO I NEED TO DO TO REPLACE WATER PUMP AND FLUSH THIS MOTOR OUT....UNDERSTAND THAT ON THIS MODEL THE TIMING CHAIN COULD RUB OR PUT A HOLE IN WATER PUMP....IT JUST PORES OUT WHEN I TRY TO FILL....HOW HARD IS THIS TO DO MY SELF OR WHAT DO SHOPS CHARGE....ALSO SHOULD I HAVE NEW TIMING CHAINS INSTALLED....THANKS...