4.3.3 OS and now I have wifi issues

since I upgraded to 4.3.3. both devices (iPhone 4 & iPad 1) are having issues in reconnecting to wifi.

It started intermittently with the IP4 and now the IPad has won't connect and now it's all the time with both devices.

Previously, just a power reset of the AEX would cure it - now zilch.

I've tried setting up the Airport Extreme network again several times in various configurations - permanantly assigned IP addresses to each device, etc.

I have several other devices on different OS and they don't have any issues.

Anyone, please any ideas? It's bad enough living behind the GFW.