I have a 1991 Mazda 626 5 speed transmission and i ran the motor to let it get warm, i pulled the oil dipstick to check oil level and oil mixed with water was spewing out of dipstick?

Spark plugs are leaking water well 2 are is my engine a rebuild?

This happened after adding the same brand fuel and may have been when the new fuel entered the engine.

How do I determine the battery size and what is the best place to get a battery in the Northern Virginia or nearby areas of MD or DC. I just need the battery, not changing the cables. Thanks!

About how long would something like this take to be repaired? Also, if the fan does not necesarily need to be Replaced, will it be cheaper?