I would recommend dividing your desired goal into smaller parts, so that you can ask specific questions about those parts (which are more likely to get accurate answers).

You will need to use sockets. Have you used sockets in VB before ?
If not, you should search the web for some examples and try to successfully connect to the router. If you find problems connecting to a remote socket, then you post your specific problems/doubts.

After being able to connect, you will have to send the username and password. You will also have to learn how to read the router’s response. These are specific tasks, and you will probably find specific problems, which you can post here.

Posting the whole problem description and asking for help without specific details, will probably get you broad and inprecise answers only.