Those readings have the 5V too high (4.75V-5.25V is the tolerance range) and your 12V is a little high (11.4V-12.6V is the tolerance range). Don't worry about the -12V or -5V. You may be getting innacurate readings from HW Monitor. Your mobo mfr likely has a utility that allows you to monitor voltages; I would download/use it. Is your system stable?
That asus probe, is it a real multimeter or a software solution?
The software meters are not always accurate. If those readings are accurate though, then yeah you probably need to see for a new PSU.
the important readings are just too high.
Nice PSU and more than sufficient for your system. Are your temps good? Have you recently updated drivers, windopws update or made any hardware changes? Looking for a change in the system that may be associated with your instability...
What are the symptoms of your instability? have you checked your system event log for errors?