Bad news....
Q1) "I re-read the judgement papers and it says interest at 11% per annum, but does not specify a date to have it paid."
A1) That is because the courts don't set a 'payment schedule'. That is up to you and the judgment creditor to establish. But, interest accrues at 11% per year (based on a daily rate) for every day that your judgment isn't paid!!
Q2) "I heard from a third party today that she (the one I am supposed to pay) is threatening to go to the sheriff and try to seize some of my property. Can she do that?"
A2) Without knowing who this 'third party' is, I can't tell whether SHE can do anything, but I can say that the judgment creditor CAN enforce the judgment as provided by law. And this includes having the sheriff serve a 'Writ of Execution' on you and seize any non-exempt property.
Q3) "is there a certain time period that needs to pass first?"
A3) The only time requirement before enforcment is that time allowed by state law for you to appeal the judgment (usually around 30 days). Since this judgment is over a year old, the appeal period has expired and the judgment is enforcable immediately!
Q4) "if she can do this, will sending a small payment to show I am trying, stop her from taking anything?"
A4) Possibly, but not necessarily. Most judgment creditors are only interested in getting paid. And a debtor (you) could contact the creditor and try to negotiate some payment schedule. But, the creditor is under no obligation to accept anything less than immediate payment in full.