ISA server 2004 on DSLL or ADSL without static IP

Sir,

I have one 2003 windows domain ,and i have connection from local ISP without static IP, they setup one wireless router , this wireless router has private ip address like 192.168.1.102, sub: 255.255.255.255.from this router i used ethernet cable to my network switch, from here we all are getting internet, But now i want to install ISA on win 2003 domain controller, while installing ISA LAT can define coz we know the local address range. Now for second NIC which ip address can i give? coz i don’t have static IP from ISP, can i use 192.168.1.102 for my second NIC ip (for both can use NIC and router lan address), pls suggest me how to configure second NIC.

Thanks.