Need some advice on a router

Copied from another section as this area may be better place for advice

Currently have a USR019108 used for WLAN for couple of pc's and 2 xbox 360's. I am happy with the router apart from a couple of annoying issues.

Random wireless disconnects on occasion (must admit haven't done any channel switching yet and that may sort this one out)

More importantly I have issues with getting a consistently open NAT status for the 360's. I have tried using uPnP or DMZ + port triggering and neither will maintain the open NAT. I can use the 360 live test and it will show "open" but sometimes an hour later, without any disconnects, the connection test will show "Moderate" or "Strict" after getting problem joining games.

Is there anyone that can recommend a solution to my problem with the NAT or can recommend a router that will give me the open NAT across both 360's

Thanks in advance

what ports in/out does an Xbox use ?