Something to try is to turn off IPv6 support in your networking preference control panel for wireless, and even for ethernet if you are hardwired.
Mine would drop connections randomly and I'd have to mess around and eventually would pull its power and let it restart to restore sanity. Then, I read somewhere it was a problem with IPv6 support, and turn it off on our Macs. Now it's very stable.
I stopped using it for my wireless router, and now use it for AirTunes. Very seldom will it lag, and when it does it'll sync up again by itself. I really can't remember the last time it "weirded out" on me, even though some days I'll be playing music through it for most of the day.
There are multiple ways to change which access point you connect to.
Using the GUI
Open network in your system preference
use the Join other networks and find the airport Express in your WiFi choices
check the Automatically join this network.
click on Advanced and move that access point to the top of your list.
If for some reason this does not work then use the Terminal
There are 2 or more ways to select the network using Terminal.
There is the ifconfig command line, which is in depth network setting, I would not use that one right now.
the other is Networksetup command line which is replacement for the GUI method mentioned above.
You would use the output from the airport command and the networksetup utility to adjust properties such as connecting to a new Wi-Fi network.
First, scan for networks with the "airport -s" option (you can skip this if you know your SSID you want to use.
and then use the SSID of the listed networks with the
networksetup -setairportnetwork <device name> <network> [password] command.
should be the "en0" which is your WiFi
or
networksetup -switchtolocation "location name"
Best Answer
You can find out which chipset you currently have installed in your Mac with the following command:
You should get a response similar to the following:
This tells us we've got the Broadcom BCM43xx series.