Deployement of app with db

Question

Hi all.... i have created an app with visual basic and sql server ... i published it .... but when i run on any other computer i cant connect to my db ????????  -by the way the connection that i have used is

 

Dim cn As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Gerti\Documents\Visual Studio 2010\Projects\BAR_RES\BAR_RES\CoffeeDatabase.mdf;Integrated Security=True;User Instance=True")

PLEASE HELP  i know i should change  the conn string but how??