[Plugin: Contact Form 7] how to reformat the HTML structure of the WPCF7

I need to touch on the HTML structure of the form. for example, changing the <span> to

• etc. How where should I do that on the source?

Also, how should I fix this? http://test.linguasg.com/wp-content/uploads/2011/12/aa-213×300.png

http://wordpress.org/extend/plugins/contact-form-7/