remote network and lan in win2000

i’m having a w2k server in office to which i am connecting through a leased line in my home. i am using terminal service for the connection. it is working good. now if i added 1 more computer in my home. i am using two nic in one pc which is connected to the office. with ips say 100.10.1.8 which is office connection, & 100.10.1.9 for the new computer connection. new computers ip is 100.10.1.15 the problem is that from the new system i am not able to use terminal, old one works cleanly. server ip is 100.10.1.0. the ips 100.10.1.8 and 100.10.1.0 is given by a third party who provides the connection. is there any way i can solve it.