How to upload a csv file which has email addresses, send html email on regular time and qty?

Hi
I use System.Web.UI.HtmlControls.HtmlInputFile to get a csv or excel file.
The file contains email addresses, subject and receipient name.
- There are input for start date to send: 20080915 (= 2008-09-15)
- There are input for start time to send: 153000 (= 15:30:00)
- There is input for time interval to send a certain numbers of email: 15 (= send emails / 15 mins); 180 (= send emails / 3 hours)
- There is input for numbers of email to be sent each time interval: 10 (= send 10 emails each time)

I built the aspx form with a submit button, backend is C#. I use System.DateTime to get current datetime.
I know how to input data into database through input textbox.
I know to use System.Net.Mail to send email  with the 4 parameters (string from, string to, string title, string content)

What do I not know how to do are:
1. How to read csv or excel file data row by row?
2. Append the start date to send, start time ...