It is very likely you cannot... if the company is out of business, usually the 401k plan itself terminates. Loans will be defaulted, and unless put back at once and rolled over to an IRA or another qualified plan with the rest of the money.. it will be taxed and penalized..
You cannot make payments to a traditional 401 loan, in any way except through payroll deduction.
If another company had bought that one out, they sometimes will transfer the assets and reamortize the loan.. this is not common. Most likely the plan will terminate, and you will have so many days to withdraw the funds, or roll them over to another qualified plan. Since it so late in the year, the default will not likely occur until 2010--- making it taxable for that year.
If you remove the remainder of the funds, they will withhold 20% automatically for the defaulted loan.. the penalty, if it applies to you would be paid the following year, most likely 2011, for tax year 2010.