Email pledge reminders

I started working at a high school that has 2 annual drives in which parents and alumnae make pledges which they agree to pay in installments.  I was asked to mail monthly pledge reminders, but the volume is large and so is the expense.  I would prefer to email the reminders.  I'd like to export the email addresses and corresponding salutations, pledge amounts and pledge balances to an excel file, and then possibly use some kind of email software to incorporate the information into the body of emails and do an email blast.  I don't think this is something Online Express can do.  I was told that it probably could not incorporate gift information into the body of an email.  Am I on the wrong track?  We don't have Net Community, and there is some resistance to using it with our website.  What is the best way to handle these pledge reminders?