Hi there,
Can you bump that rate up to 54 or so? Try playing with the setting on the wireless cards on the laptops or what have you. Also check the settings on the router as well. Make sure that all of them are sharing the same basic settings, like rate and channel. Different cards come with different things that one can play with, different softwares, no two being a like it seems. So I have found that one needs to play with those settings a bit to find that perfect "sweet spot" between card and router. That might help a lot.
Also, as I and others have said before, try re-booting the entire network from the modem out. Routers and modems are just chip based little things themselves and they too need to get their instructions straightened out now and again. For what it's worth I've gone thru a few routers over the last few years and nothing has come close to the reliability and stability of the Netgear WPN824 RangeMax we have now. It's the one with the seven internal antenas that constantly adjusts itself to your networks conditions. Don't bother with pre-N or any of those others until the standard is offically released and "standardized" once and for all.
Here's my two cents. I paid two different companies lots of money to install and set up my networks here in the office for my first two routers (Linksis, weak; and D-Link, alright?). When I bought the Netgear I also went to B&N and bought a copy of "Wireless Networks for Dumbies" or something like that, the yellow one. As I read and learned more about the subject I started to look over the settings my supposed "gurus" had set up. I quickly realized that these expensive "gurus" weren't setting up my network half as well nor half as secure as I ended up doing myself. If you're like most AC users you're probably pretty darn smart and willing to tinker with things a bit. Get a good book for a few bucks and set it up good and tight. WPA settings, MAC addressed and the like. The first time might frustrate you a bit, but once you do it a few times you'll certainly get the hang of it. And better than most small and mid-sized "gurus".
