I have belkin router but now i want a usb adapter for laptop on the go

(1) Away from home - you want to connect with your home router and internet account?
Or
(2) In the home, in another room, you want to connect with your home router and internet account?

If your a Virgin cable user, checkout their bundles home/mobile broadband deals or whatever your ISP offers.

If no bundles, get yoursellf a cheap contract 3G dongle with a data limit/price to suit you. Check which service provider has best coverage in the areas you will visit.

yes i want to use it away from home

The only way you could do that was to connect - over the internet - with your home system.
And you'd already be connected to the internet - so? What's the reason for wanting to connect via your home account when you're away from home?

As das_stig mentioned, there is only two ways to connect to the internet when away from home:

1) Contact a cell provider, and get one of their USB dongles
2) Do what a lot of us do: Go into a place that offers wifi, and use their wifi. It might cost you $5 or so(depending on the place, but some require you to purchase something), but it's worth the price if you really need to go online away from home.