Only option then would be to find a portable HD radio and connect using the AUX input. Best option is to replace the factory unit with an aftermarket radio that has HD radio and XM.
My little bit of research on the portable HD radios shows that aren't the best at getting good signal strength.
2012 JKU Sahara "Clifford" the Red Jeep - Body colored hard top, Trailer Tow, Connectivity Package
Added: 13" Eurostyle flexible antenna, Bestop SuperTop NX, WeatherTech Floor Liners, Spiderwebshade Trailmesh, Midland 75-822, Cooltech GateMount, 3' Firestik, Rubicon X wheels, BFG Mud Terrains
Jeep Jamborees: 3