Hi,
I’m not quite sure what exactly do you mean, but you can register BizForm event methods also in code behind of your web part. You can find examples on how to do this here:
http://devnet.kentico.com/Knowledge-Base/Web-parts---Controls/Making-BizForm-fields-inactive-after-submitting.aspx
Regarding your second question, you can simply add two fields to your BizForm and let users to submit this information with the BizForm. Then you can get the information using following code in some of the BizForm events:
this.<BizFormControlName>.BasicForm.DataRow["BizFormFieldName"]
Best Regards,
Miroslav Remias