Router suggestions

Just a few questions regarding my flats fairly old Belkin F5D7633.

I've updated it to the latest firmware release 1.00.25 but seem to have run into a problem where my flatmates are thrown off (they're all wireless) after around an 1hr of being connected. Never had this problem with previous firmware versions however the balance of bandwidth was ridiculous where as now it appears to have greatly improved. The only suggestion Belkin have offered on their website is changing the wireless channel.. how exactly does this help?

Another thing, the new firmware version includes WMM QOS. Does this work for online games as well as VoIP for example?

Cheers guys :)