Try an Alpaca Bike Rack. Google the name. I don't have the web address. These racks work great on all bikes but especially recumbents. I have a long wheel base and this rack carries the bike rock solid where most on the other racks teeter with the bike on them. They are well priced and well made. Buy direct from manufacturer. Speak to manufacturer direct as well. Great people. Small Canadian company.
Misslexi, did your Prius come with a 2 inch hitch or did you have someone custom weld it up for you? We have a Prius (2006) and they did not recommend towing anything with it and no hitch was available for it, at least at the time.
So I fabricated an aluminum and steel hitch that will accept a rack that I also wellded up out of aluminum. Works great.
I was surprised you said you had a 2 inch hitch on it. Do you mean a 2 inch reciever hitch or a 2 inch ball?