Web site atuomation via python

I need to verify data contained in an excel worksheet against a database. The access to the DB is via a web page so I need to login and then manually enter lots of information and submit it one at a time.

So far I have been able to automate the login process via selenium (easy) and Python, my problem is that the web application is written is such a way that once logged in, the original page is closed and a new one is opened so my control over the original one is lost (so I guess). What can I do to gain control over the new page?

I am not a developer so, for those who are helping, please be specific. Thank you all.