Cisco Router 3600

I want to Install E1 Module on my 3640 router that has 16 port analog medem (module).

Q1. Is it possible to configure 2 different block of Ip on same router after installing the E1 Module? (Subent-Zero Ip, Interfaces Ip, Ethernet Ip, and Serial Interface Ip? If yes, How would I go about it?

Q2. After installing and configuring the E1 Module, would all my clients accounts re-configure too after installing E1 Modules?

Q3. Is there any Accounting Package that I can use for the clients?Q4. How would I go about configuring my tacacs server? and how would that help?

Thank You

Usman Yahya
ousmanys@yahoo.com