Mark,
The 2002 Hobie catalogue shows the replacement side bar at $122. Unless you know someone with enough expertise and is willing to do the repair for nothing it seems hardly worth it to repair. It sounds like it will probably fail somewhere else.
Replacement requires removing the tramp from the frame, and removing the frame from the hulls. (unbolt the frame at the four pylons and gently tap the corner posts with a wooden hammer (or 2X4) upward a little at a time moving from corner to corner.) Be prepared to catch the hulls. Also, remember the lacing pattern of the tramp. Smear some grease on the pylons when reassembling. By the way, the side bars just slide into the corner with no rivets.
Estimated time of repair: 2 to 5 hours.
Good sailing
Greg
H14, H16