using two netgear dg834gt routers to extend wireless range

I have two Netgear DG834 Gt routers and want to know if it is possible to use one as a means of extending the wireless range of my network.

At the moment the with one router contected to the phone line where it enters the house (upstairs) there is only a very weak signal downstairs.

Can I use the second router to extend the wireless range of the network?