Win XP gateway Host between subnets

I am working on a network with two subnets namely 192.63.122.0/255.255.255.0 and 192.63.121.0/255.255.255.0. I wouldlike these two networks to share resources and need to find out how this can be configured using two network card on a pc. Currently I have configured a Windows XP pc with two cards with ip addresses 192.63.121.1 and 192.63.122.223 but this seems not to work as I can only see up to this machine on both sides of the network but not across. I do not have a budget to buy a dedicated router.
The network uses Windows NT for servers.