I have two network cards in my Windows 2003 RS2 (Small Business)..and am using sql 2005 in the server and all the client mapped from the server by ip 192.168.1.100..my Q can i used anther network card with different ip and different map.
Depending on the cards you may be able to bind them together using link aggregation, teaming, 802.3ad, whatever you want to call it. Also depending on the cards you may need a switch which supports this setup, or they may have an option that does not need any configuration done on the switch. If setup properly this would give you a 2gbit link, and just 1 ip address that you could continue connecting to the server with.
I would google the type of network cards you have and 802.3ad and see what you find. You could also do what you mentioned and just have both card setup individually, you would just have to manually select which ip you connected to which is sort of a hassle.