About my transmission gear shift

What is your question?

My Mercedes Benz is automatic an it won't shift gears it's stays in first gear an ills up an won't change out the oil an transmission leaked out of it when I had it sitting down for awhile after finding out my alternator went out I replace it an the car starts up jus find fully powered but I can't drive over 20-30 mph because it won't shift gears what could be my problem??