I have broadband 750 unlimited plan with asdl modem,how yo share it to other computers
I have also lan connection

Hi

You can share the internet using the proxy softwares from your system
But in this way you will face many problems, like it will disconnect after some intervals

My Suggestion is to use the below d link router
It's the best product

D-Link DSL-2540B ADSL2/2+ Modem with 4-Port Ethernet Router