VPN configuration Netgear Pro Safe FSV114 LAN TO LAN / GATEWAY TO GATEWAY

I have 3 locations, and need to make VPN tunnels between these locations. The locations have these specs.

Site 1: Main location with the servers hosting exchange, Domain controller and more

WAN IP (EXAMPLE NOT REAL). 24.56.76.220
IP on ISP ROUTER (192.168.1.1)
IP on NETGEAR FSV114 Firewall (192.168.1.100)
IP on servers 192.168.1.2, 3, 4 , 5, 200 (Has 5 ip addresses given to 3 servers) Not relevant for the VPN setup, Just to give a idea what is to be set up. Its Windows 2003 servers.

Site 2 (There is no firewall from the ISP HERE)

Wan IP (NOT THE REAL ONE) 80.45.34.23
 IP on NETGEAR FSV114 Firewall (192.168.2.100)


Site 3 (There is no firewall from the ISP HERE)

Wan IP (NOT THE REAL ONE) 81.69.34.23
 IP on NETGEAR FSV114 Firewall (192.168.3.100

1: The first question is what ports do i Need to forward on site 1 from the ISP firewall with ip 192.168.1.1 to the Netgear FSV114 Firewall to get the VPN tunnels working. I have found that these ports should doit, and will be enogh to make the VPN tunnel from site 2 and 3 to the main site.

GRE 47
PPTP 1723
IKE UDP 500
UDP / TCP 88
1701 L2TP UDP / TCP

2: QUestion 2 is about the VPN tunnel design. Do I need to make VPN tunnels between all the sites/locations, so that site 1 har a configuration that har a VPN conenction to site 2 & 3 and site 2 has vpn conenction to site 1 & 3 and Site 3 har VPN connections to site 2 & 1?

Hope someone can help me in my questions