Add a second web server and create a NLB

Hello everybody,

I am new in NLB.Windows Server 2008 R2 - NLB

Currently my infrastructure has a unique machine working as web application (hosting a web site).

The new requirement is: improve load request and continuity, therefore

1) Adding another machine

2) Host the same website

3) Intergrate with the existing Web Server: NLB (Network Load Balancing)

My question is: Do I have to install the web site on the second machine (it requires 2 days) and then make the NLB? 

or is there any opportunuty to copy (extending or silmilar actions) the web site in the first machine to the second machine?

Thanks