Mkvedadi

My satellite for my 2009 GX470 keeps losing signal. I brought it in and they said the antenna is bad and will be around $500 to replace. I held off as I felt that was really high to replace the antenna. I called them to check on the part cost and they looked and said that it is discontinued and I would need to get an aftermarket one added.
I have the Levinson stereo system. Does anyone know what my best option would be?