ADSL2 modem -> WiFi router - How?

I am fed up with O2 Wireless box II. It restarts 10 times per day and is useless in general. I have D-Link DIR-301 WiFi Router laying around and could use it instead but I also need a modem, don't I?

What do I need to buy and how to connect those two?

[Admin]

Hi There

It's quite often simpler and cheaper to just buy a new modem/router combined rather than trying to get separate modems and routers talking to each other.

I've always used Netgear routers and never had any problems with them.

I hope this helps
Admin

New ADSL router = at least 30GBP
New ADSL modem = 1-3GBP

Not so sure if the first option is cheaper.