Fire up the Loran, go into setup, and set it for Latitude/longitude mode instead of TD mode. Then look up each waypoint and write down the lat/long. Enter those in your GPS and you are done. That's the easiest and most accurate way since you still have the Loran.
If using Lat/long. mode on the Loran is problematic, the other alternative is an $85 software package named LoranGPS that will do the conversion.
http://www.andren.com/index.cfm