i have installed nginx but now i want to install headers-more-nginx-module into existing installation of nginx , so can someone tell me how to do it ?

i have found following commands but it is with the new installation of nginx and then headers-more-nginx-module

wget 'http://nginx.org/download/nginx-1.2.4.tar.gz'
    tar -xzvf nginx-1.2.4.tar.gz
    cd nginx-1.2.4/

    # Here we assume you would install you nginx under /opt/nginx/.
    ./configure --prefix=/opt/nginx \
        --add-module=/path/to/headers-more-nginx-module

    make
    make install

currently i guess my nginx is under where the nginx.conf is placed

etc/nginx