There is no "jump to date" function in the week widget. The week widget is meant to display the current week and maybe allow the user to also see the next or the previous week. To go back to the current week you can tap the date header of the widget. But if you want to see a specific week and jump to it, you have to start the app.
Please don't hesitate to contact me again if you have further questions!
Kind regards
Dominique Gunia