Hmm, depends what it is that's broken!
Is it something as simple as the gear shift lever rotating on the shaft? My FJ is like that (though at 90,000 miles it's allowed some wear!) and I simply have a huge nut and bolt on there.
If the problem is inside the gearbox, then it's a slightly different matter. You'll need to remove the gearbox and replace whatever it is that's bent or broke inside - and I'd suspect it's the selector lever. Not too hard if you're confident with spanners, as the whole box comes out in one go without splitting the crankcases.
Have a look at that shaft first though...
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