Here is what you could do. It is more of like three plugins. One main plugin and two that are sub plugins
First you will want to get Contact Form 7 ... if you don't already have it. Here is the link if you need it:
Download Contact Form 7 Here
Then download Contact Form 7 to Database. This will store whatever information you collect in the form in your database.
Download Contact Form 7 to Database Here
Our last and final plugin download is the Contact Form 7 Sidebar widget. You can get it here:
Contact Form 7 Widget
on_sent_ok: "location = 'http://example.com/';"
Replace "http://example.com/" with your own url.