I used
Plastex to repair my coffee-spiller. It sets up in
seconds. The kit comes with a "rubber molding bar" that you can use make a mold for missing parts (copy the tab from the other side, or from the correct side on a friend's truck). Then go beyond "repairing" to "improving" the piece - add more material to make the sides thicker/stronger. Check for clearance, then sand, file or grind away excess as needed. If you get excess material in the holes, just re-drill them. When finished you will have a noticably tighter fit - and a stronger cupholder.
If only one side is broke, go ahead and reinforce the other side anyhow - or you WILL be doing it later!
Plaxtex is pretty easy to work with, with just a little bit of practice. AMink, you are in luck, since the Plastex folks are in Reno. You might get them to give you a demo and show you how it's done.
FWIW, I've been using Plastex for 3 or 4 years. It is good stuff, and it is amazing what you can do with the molding bar. I am glad to see that the price has come down. I've gone thru 2 or 3 of the "master" kits that used to sell for $75.
Their website is kind of "busy" and draws you attention away from the hyperlinks for the
Online Store,
Repair Photos, and
Product Application.