Wireless internet router keeps dropping out

I've got a problem with my wireless router at home. It is a BT ADSL line (8mbit) (though we usually get 5mbit). We're using a Belkin N wireless modem router

There are at any one time between 1 and 6 devices for example:

2 x iphone 4
2 x PC
1 x XBOX 360
1 x laptop

Typical usage ranges from simple web page browsing to online gaming and HD movie streaming. The router usually drops out after 30 mins – 1 hour. Sometimes the internet will stop for a certain device and the others will be o.k or all will drop internet and we'll have to restart the wireless router to gain connection again.

We had a wireless router before this one and the same would happen. Although the range on that one was not as a good as we thought it was, we thought it was probably that so we decided to get a better one in hope that it would solve the issues. I don't think the range is the issue here though as the devices are all within about 20 meters of the router.

We have contacted BT and there are no faults on the line so we are thinking it must be the wireless router.

WPA2 (64-bit key) encryption has been setup and I have tried various settings on the router. It has always been set to using band B, G and N. I have tried setting it to just G but with no luck. I have also tried changing the channel around from 11 to 13 but also no luck. The channel mode has also been set to 20/40MHz which is apparently a recommendation. We are also running a firewall built into the wireless router and are also running the latest firmware.

It might also be worth noting that connecting to the wireless router via network cable does not have any problems with dropping out.

It seems I am not the only person to suffer with this problem as I've come across a few posts on the internet from people with the same problems. I have been reading this article http://www.pcmag.com/article2/0,2817,2399897,00.asp and apparently a dual band wireless router helps with crowding and also enabling WMM is meant to help with streaming multi-media. These features are not included in my router.

So I guess I have a few questions here: Is my wireless router recommended for the type of use that i'm currently using it for. Ie web browsing, video streaming, gaming etc.

Should I be using a better make/model such as CISCO? Would features like dual-band and WMM make a difference?

Does anyone have any recommendations to solve this problem? Maybe it's something else other that the wireless router?

Thanks in advance!