Use wired.
Or get rid of the fisher-price router NTL give you. They're terrible (i'm on the same set-up, but use the Wired connection for playing online games).
The USB dongle thingies aren't the best either.
Id agree with Carnifax, get a card for the PC and avoid the USB dongles as they just arent as good.
If you still want to run on a wireless set-up then get an up to date router. Ive just gone for a new one (my old one was a Netgear 802.11g which crashed every few days and I now have a 802.11n) and my connections are now flawless and my range is a lot better.
Still wireless networks arent perfect in the same way that cell networks arent, and both are quite mature now so we might as well admit they are always going to have some problems. If there are a number of you connecting and youre getting drop outs and cant live with them get a wire. If thats not possible try one of the power line network thingys, although some CAT5 is cheaper and Ive never tried the power line connections, so Im not willing to say theyre better.
It's as I suspected then 
oh well, it's annoying but I can live with it.
Changing to a 300 mbps Linksys wireless N router and dongle sorted my wireless problems out to.
Hi, in my house we have wireless broadband and when playing CoV there is a notacible lag on everything, which isn't present if we swap to a network cable to the router.
Is this just the nature of wireless or is there any settings we can play around with to make the wireless gameplay less laggy?
(we have NTL broadband running through a netgear router with netgaer wireless usb devices in the computers)
Cheers for any help you can provide!