You would have to sue them, get a judgment, record the judgment (then you have a lien) then try to execute the judgment (what you can execute on is dependent on the laws of your jurisdiction). You'd have to see if in your jurisdiction the amount is enough for superior court or if you have to go to small claims court (probably your best bet since you won't have to pay an attorney for that). You can also see if your homeowners insurance can help, although many policies exclude water damage, but you can check.
Your question is a common one on this forum. The general legal rule is that if a leak originates in a condominium unit, the unit owners are responsible for the damage (for which you can sue them). If the leak originates in the common areas, the condominium association is responsible for the damage. The practical solution is to make a claim under your condominium owner's insurance policy for the damage and let the insurance company sort out who is responsible. Too many people make the stupid mistake of not carrying condominium owner's insurance policies and are stuck with problems like yours.
Disclaimer: This answer is provided for informational purposes only, does not constitute legal advice, and does not create an attorney-client relationship. Actual legal advice can only be provided after completing a comprehensive consultation in which all of the relevant facts are discussed and reviewed.
You would have to file suit in court to get a judgment lien and go after the property. If the claim is $5000 or under you can file in small claims; over $5000 to $15000 is county court.
Hopefully you have insurance and the insurance can deal with it.
This communication is not intended to create an attorney/client relationship. It is always recommended you consult an attorney in person to discuss your case. The Law Offices of Stage & Associates practices state-wide and represents homeowners and community associations. Please visit our website at www.stagelaw.com.