I have found the wifi-crash soltution. Maybe some one interested because it seem that a lot of people with atheros-based PCI card are experiencing problems.
Now from an old post, I found the IO80211Family.kext from a 10.5.1 iatkos DVD, the solution in order to use my d-link DWA-547 with all cores enabled. Now the system is stable.

Still need investigating for sound and sleep but now the situation is much better!... thanks to all.