What are the symptoms of your crash? Freeze? Reboot? something else?
Do you have another power adapter you can try (with the same or ideally higher current capacity)? Sometimes a failing or marginal adapter will cause the device to brown-out during high bandwidth periods.
What about wired? Does the wired networking also stop functioning, or is it okay?
If you have something with more capacity, yes, double would be great.
It's hard to check directly, but the larger power adapter would be a good start for at least the external supply.
This may be a bit intensive for your device.
This may be a useful bit of information:
Another thing to check is if the uptime on the device is getting reset. If it goes back to zero (and by the time you check is a pretty short time), that does indicate a crash + reboot, but if the uptime is not getting reset, the problem is not a full crash + reboot.