Thank you Duff-Man.
I only upgraded to 10.8.3 from Snow Leopard just this week and have been having no end of dropped wi-fi problems so was thinking of trying the 10.8.4 update to see if that helps. But from what I have been reading here, 10.8.4 hasn't fixed the wi-fi issue. Wi-fi was rock solid on my iMac with SL, but then my iMac came new with SL as its OS so it would have been a squeaky clean install. I am seriously considering taking it into my local mac dealer and having them wipe my drive, reinstall Snow Leopard and restore my data from the Time Capsule. I cannot accept this flakey wi-fi issue. The only reason I upgraded (and I say "upgrade" sarcastically) is because the new Lightroom 5 that is set to be released won't run on SL. But right now, I'd be happier with my Lightroom 4 and stable wi-fi on SL.
Sorry, just had to vent!
Diane