I'm not too clued in on this, but can't you do a DIY fix on it? I mean, there's gotta be some way you could improvise it to have a decent fix on the handlebars?
Duct tape, glue, blutac, steel ties, cable ties, using other handlebar brackets and making them fitttt..
But I did have an issue like this once with a cheap 'n nasty cycling computer, In the end I filed the back of the computer smooth so I could glue this piece of plastic rectangle on it.. Not before drilling the piece of plastic a fair size hole in it, so I could run a cable-tie through it and wrap it over the bars (or stem if you want)
I'm not much help without better pictures, though.