First up, does the movement go into hand setting position ok?
does the date change over ok when the time passes 12pm?
Does this movement have "quick set" date change? If so is it working ok, does the date change over crisply?
if all these functions are ok, then take it to a decent watchmaker who has a Quartz testing machine.
there are a series of 3 or 4 easy tests that will determine what is wrong with the movement.
with this information you can start the hard part of sourcing the replacement part/s.
Join watch forums, introduce yourself, be polite and explain in a sympathetic manner what the watch is, why you want to repair it, what you have done so far to repair it and lastly...what you require.
I have just read a blog "RaulHorology" he repaired one of these. Make contact, but above all do not steam in with "can you sell me the part I require"
with a bit of patience and the correct approach, you may get it running.
good luck.