You need to remove the two widgets and insert the Text Widget. To do this, login to your Dashboard and then:
Click on: Appearance >> Widgets
On the right hand side you will the Widgets titled: Archives and Meta
On those widgets you will also see the drop-down button. click on them one after the another and click the DELETE button/text
This will remove both of them.
Now in the middle, you will find various Widgets. One of then is called Text. Drag it to the side bar and it will open for you automatically to the necessary editing and to give it a title. Don't forget the Title to this.
Hope this helps.