Big Water leak in ceiling - Who to call?

[Brian5000]

Hopefully this is an easy one...
I live in Chicago in what we call a 3-flat condo building ... one big house with 3 units stacked on top of each other.
I am in the 2nd floor sandwiched between my neighbors' units above and below.
Recently a rather large (~5 ft long) ceiling leak developed in my ceiling and has stained the drywall.
There is no sink or bathroom above this area, so we think it's caused by a leaky pipe running through my ceiling (under my upstairs-neighbor's floor).
It has now leaked two times in the same footprint while my neighbor was away from home.

Here's some photos:

http://i.imgur.com/A52fPQ5.jpg
http://i.imgur.com/35EErQD.jpg
http://i.imgur.com/UNqh8do.jpg

I have no expertise in this kind of drywall/plumbing repair.
To get this fixed, do I call a plumber? A dry-wall guy? A handyman?
Also, should I ask my neighbor to help pay for it? (Is it my ceiling or her floor that's leaking?)
Any other advice would be appreciated.
Thanks.

[ShoulderThingThatGoesUp]

I would say a plumber. Ideally your HOA documents will specify whose responsibility it is to pay, but first you want it done.

[zolotiyeruki]

I would say a plumber. Ideally your HOA documents will specify whose responsibility it is to pay, but first you want it done.

Yup, call a plumber.  And your neighbor, too :)

[Brian5000]

I called and got a plumber coming by in a couple days.
The plan is to have the plumber saw thru the drywall and fix the leak.
Then I'll call a drywall guy to patch the plumber's hole in the ceiling.

Also good idea with the HOA docs. I'll look into those.

Thank you for the replies.

[waffle]

I would cut out the soaked section of drywall yourself now. Not only will it save you a bit of money, but it will also let you see what is going on, and put a bucket below the leak so it drips into that rather than soaking and ruining more drywall. Also once opened up you may find that it is something super simple that you can fix yourself (saving more money), or that its something major and you need the plumber out ASAP.

[couponvan]

Drywall is easy to cut into - and that plumber is going to charge you by the hour. If it takes 15 minutes you save $25-30.  Now if it is your neighbor's responsibility then leave it as is. ;-)

[Cwadda]

Have you considered filing an insurance claim? Or having your neighbor do so?