Q: Wifi still dropping in Yosemite 10.10.1

Running on MacBook Pro Retina late 2013.  Updated to Yosemite 10.10.1.  The WiFi still dropping repeatedly.  It will drop and reconnect every few minutes.  I thought 10.10.1 suppose to fix the WiFi problem.  Tuning on and off the Wifi didn't help.  Turn on the diagnostic didn't help.  My machine require proxy service to connect to internet.  The WiFi seems to work fine at home when the proxy server is not use.   Any helps?