Assuming that the new card is working, ie ifconfig shows eth1 as the network interface, and you can ping successfully from the box, and ping it from others, there is no need to reinstall, from what I remember you need to go into fog settings, and change the instances of eth0 to eth1, and then go into the storage node settings, and again change eth0 to eth1.
Thia worked at 0.32 and I don’t think it will be any different at .33