Asterisk Configuration Project

I have Asterisk installed and working properly for my company. 90% of the features I am able to do. What I would like to add is the ability to have 3 external lines (already purchased from broadvoice). When dialing out, they must check for availability. Same with incoming calls. Here is an example. [login to view URL] I also need the ability for a user to dial a sequence of number and have there extension forward their calls to an external line (i.e. cellphone). That's It! I'm sure it's simple and there are thousands of examples on how to do it, I just don't have the time to mess around with it. I have all the broadvoice phoneline SIP information available, etc, etc.