You probably can't collect, unless the defendant was driving under the influence. In that case, you might be able to pursue a nondischargeability complaint within his bankruptcy case.
If he was not driving drunk, then it is probably a simple negligence case, meaning that the debt (and your judgment) would typically be dischargeable in bankruptcy.
Just because the person SAYS they are going to go bankrupt, doesn't mean that they will. Until they actually file bankruptcy, you can go after them all you want. But be very careful. If and when they do file their bankruptcy petition, you cannot make any attempts to collect from them. If you do you may be liable to them for damages for violating the automatic stay that goes into effect when they file. If you feel you may have the right to go after them even after they file bankruptcy, you must make a motion to lift the automatic stay first. Be sure to consult with an experienced bankruptcy lawyer.
If you are a creditor and you receive a notice that the person who owes you has filed a bankruptcy, you must immediately stop attempting to collect the debt. The bankruptcy notice will contain a notice entitled "deadline to file objection to discharge" which will give a date. You must speak with a bankruptcy attorney to determine whether you can object to the discharge of your debt. An objection must be commenced prior to that date. The objection is called an "adversarial proceeding", and your objection must be based upon one of the listed reasons for objection found in 11 U.S.C. Sec 523 (Chapter 7) or 11 U.S.C. 1325 (Chapter 13) . The most common objections are based up an allegation that the debtor engaged in fraud in the making of the debt, or willfully defeated collateral. Most attorneys charge a fee based upon hourly billing. Expect a trial on the matter between 3 and 12 months depending upon the judge.
Probably not. once filed, a bankruptcy, immediately stops actions against debtors by creditors, collection agencies and other entities. By trying to collect your judgment you would be a creditor, and would need to hire an attorney to get relief from stay to pursue your judgment. You will need to file a claim.