problem with SHDocVw

I want to get information from an Internet Explorer window that is not opened by my application. I can successfully do so with one opened by my app. How do I set to the current IE page?

Here's an example of the code that works:

Dim ie = New SHDocVw.InternetExplorer()

'open new browser window

ie.Visible = True

ie.Navigate("www.lisbin.com")

url = ie.LocationURL

ie = Nothing