Application automating webform input

I am trying to create a windows forms application in c# to do the following: Query a microsoft DB, set textboxes on the form to those values, and load a third party form in the webbrowser control, then set the values in the third party forms to the values in the windows form.  So, txtBoxFirstName on the main form would fill the input field for First Name on the third party form that lives in the webbrowser control.  I'm stumped.