Router advice

[Target]

A friend of mine bought a wireless router for his office a couple of years ago which was fine because he didn't have internet access at the time.

Now he's looking to get broadband set up and was wondering whether it was better to replace the router with a modem router or just attach the supplied modem to the existing router

Advice welcomed

 

[Target]

It's ADSL. The current router (Netgear 624, I think) has a USB port built in. Can the modem be plugged into that? If not, how will it work? I know that with an ADSL router the authenticating is done by the router

 

[Target]

My mistake, this is the current router:

http://www.netgear.com/products/details/WGT634U.php

Does that make any difference?

I recommended the Netgear DG834PN, do you think I should push this product onto him?