The details of your scenario are lacking, but I'm assuming you are referring to fully secured, fully amortizing, real estate note, or something similar with good collateral that isn't going to disappear overnight.
Assuming no balloon payment, then here is what you do. Take the number of periods left (N), the monthly payment amount on the existing note (pmt), insert $0 for future value (FV), 1.5% [18%/12 months] for monthly interest rate (i), and solve for the PV. You can calculate it on Excel.
The loan discount is based on the rate. If the rate is already 18% fixed, then you could probably get the full 60,000. If the interest rate on the note is 7% fixed, then they will want a hefty discount. They are still going to collect the 7% from the underlying obligor, but they need to get 11% from you (via discounting the loan) to make their required rate of return.