Brought out of long time lurking due to a necessity of advice :(

My question is, if I have a wired connection for my PC, is there any benefit from getting a more expensive router such as the Asus RT N56U/N66U?

The problem itself however is that my router continually drops connection. I'm under BT Infinity and everything connected to my router loses connection at random times. The time between each disconnect varies a lot though (sometimes it's fine for ages, sometimes it'll be every 5 minutes).

My connection hasn't dropped in the last couple hours but my event logger still looks like this (not sure if these logs are a problem too):
The actual error message I get only when it drops though is 'CWMP: session closed due to error: Could not resolve host'

I thought it was because of a TV box we bought that works through our internet connection but I'm not 100% sure since it sometimes happens even after I've disconnected it too. The other possibility was it could be because my router is connected to my modem by a fairly long (15m I think) cable.

Most probably though, I thought my router was the problem (either by being generally faulty or just by having problems with the tv box). I called BT and they said it was no problem on their end.

I thought a solution might be to buy a new router hence my question about whether getting a more expensive router will give me superior line quality for gaming/general pc use. If it ended up being my modem was the problem, it's also possible to use the BT Home Hub 3 as a modem instead isn't it?

Appreciate any in put :S