Although your question is quite vague, I believe you are saying you have a Beetel 450TC1 ADSL Modem/Router and have switched from ADSL service to a broadband service that gives you a standard Ethernet connection for Internet access?
You should get a different router, one that is a real wireless router and not a ADSL Modem/Router combination. ADSL Modem/Routers in general have no provisions for external Internet access, such as from your new broadband connection, it expects the only Internet access to come from the ADSL connection (which you no longer have). It is likely not possible to make it work as a "standard" WiFi router, especially given it doesn't have the correct interface.
Your best course of action would be to acquire a standard wireless router. Given that you do have a USB dongle, and I assume your computer has a wired Ethernet connection, it is possible you would use Internet Connection sharing (Hotspot), but that would depend on your operating system and setting it up is outside of the scope of these answer, but there are multiple tutorials online for most operating systems that are capable of it.