If you give a machine 2 ip addresses, one from each subnet ( one gateway), it will be able to communicate via ip address to the second subnet.
To do this:
Control panel
Network connections
Right click on the network connection
Properties
highlight internet protocol tcp/ip (version 4, not 6 if both are listed)
properties
Make sure that original set of ip addresses is set
click advanced
add an ip address from the second subnet and the subnet mask
ok, ok close.