1) To make bulk calls, you need Asterisk + a script to feed it numbers, plus a place to deliver calls to (a VOIP provider/telephone company)
2) I'm assuming you're using the Originate command in the manager interface. If so, add a callerid line to your Originate command. For example
Callerid: "James Sharp" <18005551212>
Will set the originated call to use that CallerID.