fakeer

Here's required info:
Connection: Sify Broadband DSL
Router: Linksys WRT54G2
8 PORT Router: 4 Ethernet, 4 Wireless

3 laptops behind my router all connected via Ethernet.
All having IP: 192.168.1.10*
Subnet: 255.255.255.0 (obvious though)
Gateway = Router IP = 192.168.1.1

Sify DSL cable goes into router's Internet port and my Sify IP is :10.39.42.231  Subnet: 255.255.255.0

Now what I want is to configure my router or OS (or whatever) so that we can (all three laptops) share with outer network i.e other Sify users of my hostel and area within the same IP range as above mentioned.
How should I go about it?? How to map the different IPs (router's i.e. our internal network's and Sify's) so that we can connect  and share with other Sify subscribers i.e PCs with IP 10.39.42.*** (and so on) These are mostly directly connected to Sify's DSL network and are 100% windows systems with their folders shared. I want to be able to access their folders and/or let them access mine.