I agree with the above, that the direction you are going in may not be the best but, to answer your question...

There are a couple of ways to accomplish an auto response email. The easiest and cheapest (free) way would be to create a generic email box in Exchange. Open it with Outlook and create a rule that will respond to the emails that it receives.

Note there are 2 types of rules, server side and client side. creating a server side rule will allow the rule to process without requiring a client to be attached.

That should get you started...

m2