If you need to find out what channels your neighbours wi-fis are using, there's a free programme called Inssider (nothing to do with Mr C.) which will show who's using what.
inSSIDer | MetaGeek
As you mentioned 'router' I guess you're using an ethernet cable - if you're using a USB connection that's only good for a max of 4 meg. (So I've been told - could be bollox)
We've got BT Infinity, which goes like the clappers; but it will disconnect for a couple of minutes every once in a while while it re-adjusts its whatsits.